Single use medical device apparatus and methods

ABSTRACT

A medical device includes a printed circuit board-battery assembly, a tape encapsulation assembly wrapped around the PCB-battery assembly, and a second removable tab positioned on a surface of the tape encapsulation assembly. The second removable tab provides an adhesive layer on a surface of the medical device when the second removable tab is removed from the medical device. The PCB includes the electronic circuitry that performs the functionalities of the medical device, including an optical sensor that comprises at least one light source to emit light towards a measurement site of a user and at least one photodetector to receive light returned from the measurement site. The medical device can connect to a host computing device that performs various operations, including, but not limited to, authenticating the medical device, causing measurement values such as blood oxygen saturation (SpO2), pulse rate (PR), and a perfusion index (PI) to be provided.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Provisional Application No.62/629,395 entitled “Low-Cost Single-Use Medical Device Apparatus andMethods,” filed on Feb. 12, 2018, of which the entire disclosure ishereby incorporated by reference in its entirety.

BACKGROUND

Pulse oximetry is a technology that enables the non-invasive monitoringof a patient's arterial blood oxygen saturation and other parameters.Medical devices that relate to pulse oximetry are implemented inclinical settings as well as in fitness and wellness applications. Forclinical or otherwise “critical” applications, a medical devicetypically includes complex electronics and signal processing, which caninvolve relatively high manufacturing costs and power consumption.

In fitness and wellness applications, a reusable medical device istypically used. In some instances, the reusable medical device is awireless reusable medical device. However, due to the power consumption,weight, size, and ergonomic issues associated with the wireless reusablemedical device, the wireless medical device is used for a limited amountof time, such as during breaks that occur throughout an exerciseactivity. For example, conventional reusable wireless oximeters can beheavy, only present measurement values as integer numbers (e.g., nodecimals), cannot display oxygen saturation values above one hundredpercent, and may not be designed to be attached to the user duringexercise or similar activities. As a result, users typically take breaksduring exercise (e.g., stop exercising) to measure their oxygensaturation with a pulse oximeter. The users may also measure theiroxygen saturation before and after exercise. However, this process maynot be very effective given that the users cannot obtain measurementsduring exercise. Additionally, the users cannot expand theirphysiological limits, such as maximum heart rate and improved oxygensaturation, in real-time during exercise.

SUMMARY

In one aspect, a system includes a medical device and a host computingdevice. The medical device can include a printed circuit board-batteryassembly, a tape encapsulation assembly wrapped around the PCB-batteryassembly, and a second removable tab positioned on a surface of the tapeencapsulation assembly. The second removable tab includes a two-sidedadhesive layer that provides an adhesive layer on a surface of themedical device when the second removable tab is removed from the medicaldevice. The printed circuit board includes the electronic circuitry thatperforms the functionalities of the medical device, including an opticalsensor that comprises at least one light source to emit light towards ameasurement site of a user and at least one photodetector to receivelight returned from the measurement site. The printed circuit board alsoincludes at least one contact pad comprising an ON switch of the medicaldevice. A battery is electrically attached to the printed circuit board.The tape encapsulation assembly includes a sensor window positioned overthe optical sensor, and a contact opening extending through a tapeencapsulation component for receiving a first removable tab. The firstremovable tab includes a liner layer portion disposed on a first surfaceof the tape encapsulation component covering the contact pad or pads onthe printed circuit board and a tab portion disposed on an oppositesecond surface of the tape encapsulation component. The liner layerportion is positioned between the at least one contact pad on theprinted circuit board and a conductive tape or conductive contact in thetape encapsulation component. The host computing device executes anApplication software program that performs various operations, includingauthenticating the medical device, causing measurement values such asblood oxygen saturation (SpO2), pulse rate (PR), and a perfusion index(PI) to be provided to an output device (e.g., displayed), and providingvarious user interfaces views that display one or more measurementvalues, enable a user to set one or more settings such as upper andlower limits for an alarm, enable sound or audible alarms, and the like,and enable a user to share one or more measurement values or other data.

In another aspect, a method for authenticating a medical device andpairing the medical device includes computing an original credential,such as a hash number, based on data associated with the medical device.The data can include a serial number, a model number, a lot number, anexpiration date, a version number, and/or combinations thereof. Thecredential, along with the data used to compute the credential, areincluded in an identifier that is included on a label. The label isscanned at a host computing device and the image and the identifierprocessed to obtain the original credential. An authenticationcredential is also determined using the data in the identifier. Thecalculated credential and the original credential are compared with eachother. When the calculated credential and the original credential match,a first pairing credential is computed at the host computing deviceusing data in the identifier and stored in a storage device of themedical device. The first pairing credential is transmitted to themedical device. Using the data stored in the storage device, a secondpairing credential is computed at the medical device. When the first andthe second pairing credentials match, the medical device is paired withthe host computing device.

In yet another aspect, a method includes determining whether a “SpO2Out-of-Range Suppression” setting is disabled. If suppression isenabled, a SpO2 value(s) is determined using a curve or plot that has amaximum SpO2 value of 100%. The SpO2 value or values are provided to anoutput device (e.g., a display) as an integer number that is equal to orless than 100%. When suppression is disabled, the SpO2 value(s) isdetermined using a curve or plot that has a maximum value greater than100%. The SpO2 value(s) is provided to an output device (e.g., adisplay) and represented with a whole number and one or more decimalplace values (e.g., tenths place value, hundredths place value, etc.).Optionally, the upper limit of the SpO2 value for an alarm can beautomatically adjusted to a value over 100% (e.g., the maximum valueover 100%).

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive examples are described with reference tothe following Figures. The elements of the drawings are not necessarilyto scale relative to each other. Identical reference numerals have beenused, where possible, to designate identical features that are common tothe figures.

FIG. 1 is a block diagram illustrating an example system;

FIGS. 2A-2F and 2M-2O depict example measurement sites on a patient'sbody where a medical device can be applied;

FIGS. 2G-2L illustrate example adhesive tape layouts suitable for usewith a medical device;

FIG. 3 depicts a distributed system suitable for processing signalsproduced by a medical device and an example modulation scheme that issuitable for use with a medical device;

FIG. 4A illustrates examples of other modulation schemes that aresuitable for use with a medical device;

FIG. 4B is a flowchart of a first method of determining which modulationscheme to use;

FIG. 4C is a flowchart of a second method of determining whichmodulation scheme to use;

FIG. 5 is a cross-section view of an example medical device;

FIG. 6A-6C are schematic diagrams depicting an example medical device;

FIG. 7 is a flowchart illustrating an example method of processingmeasurement data received from a medical device;

FIG. 8A depicts a perspective top view of a container that includes adisposable medical device;

FIG. 8B illustrates a bottom view of the container;

FIG. 9 is a flowchart depicting an example method of generating anidentifier for a medical device;

FIG. 10 is a flowchart illustrating an example method of authenticatinga medical device using the identifier produced in FIG. 9;

FIGS. 11A-11B depicts one example technique for scanning a label thatincludes an identifier for the medical device;

FIGS. 12A-12C illustrate an example method for activating the medicaldevice;

FIG. 12D depicts an isometric view of the medical device afteractivation;

FIG. 13 illustrates an example method of attaching the medical device toa user;

FIG. 14 depicts a state diagram of the medical device and a hostcomputing device;

FIGS. 15-19 illustrate example user interface views of the Applicationsoftware that can be displayed on the host computing device;

FIG. 20A is a flowchart depicting an example method of operating analarm system;

FIG. 20B is a flowchart illustrating an example method of producing anaudible alarm;

FIG. 21 depicts a block diagram of a first configuration for a medicaldevice and a host computing device;

FIG. 22 illustrates a block diagram of a second configuration for amedical device and a host computing device;

FIG. 23 depicts a block diagram of a third configuration for a medicaldevice and a host computing device;

FIG. 24 illustrates top views of example components of a medical device;

FIGS. 25A-37B depict an example method of assembling a medical device;

FIG. 38 illustrates a cross-sectional view of an example removablesecond tab;

FIG. 39A-B depict a method of packaging the medical device in acontainer;

FIGS. 40A-40B illustrate different configurations of a printed circuitboard of a medical device.

FIG. 41 depicts example technical specifications of the medical devicewhen used in combination with a host computing device;

FIG. 42 illustrates an example scatter plot and an example Bland-Altmanplot for a representative SpO2 clinical performance;

FIG. 43 depicts experimental points of an example calibration curve fora pulse oximetry system;

FIG. 44 illustrates a measurement user interface view of an Applicationsoftware that can be displayed on a host computing device;

FIG. 45 depicts an example settings user interface view of anApplication software that can be displayed on a host computing device;

FIG. 46 illustrates a first example Mobile Device Management system;

FIG. 47 depicts a second example Mobile Device Management system; and

FIG. 48 is a flowchart illustrating an example method of providing SpO2values that exceed one hundred percent.

DETAILED DESCRIPTION

As used herein, the term “optimal” is intended to be construed broadlyand is intended to cover values and models that provide best,substantially best, and acceptable values and models. As used herein,the term “data stream” refers to data sequentially indexed by anexogenous quantity (e.g., time, space, etc.). For instance, data streamsthat are function of time, are assumed to be indexed by time such as ina discrete-time system. Data streams that are function of space, areassumed to be indexed by space. Depending on the application, datastreams can be indexed by quantities that have physical meaning or thatare abstract in nature. The embodiments disclosed herein can be appliedto any data stream regardless of its indexing or sampling method.

Reference will now be made in detail to representative embodimentsillustrated in the accompanying drawings. It should be understood thatthe following descriptions are not intended to limit the embodiments tothe described example embodiments.

FIG. 1 is a block diagram illustrating an example system. A medicaldevice 100 is attached to one or more measurement sites from which thesensor can readily access blood perfusion information. In theillustrated embodiment, the measurement site 111 is a finger or digit(see also FIG. 2A). Other example measurement sites include, but are notlimited to, a patient's temple (FIG. 2B), forehead (FIG. 2C), neck (FIG.2D), arm (FIGS. 2E and 2F), ear or ear lobe (FIG. 2M), nose (FIG. 2N),and/or the posterior auricle of an ear (FIG. 2O).

In one embodiment, the medical device 100 includes a processing device102, instrumentation circuitry 107, a communication device 103, and astorage device 115. The instrumentation circuitry 107, the communicationdevice 103, and the storage device 115 are connected to the processingdevice(s) 102. A converter 108 is connected to the instrumentationcircuitry 107 and switching circuitry 112. The communication device 103,the storage device 115, the processing device 102, and theinstrumentation circuitry 107 along with a power supply 109 areconnected to the switching circuitry 112. The medical device 100 mayalso include adhesive tape to attach the medical device 100 to ameasurement site.

The medical device 100 may be turned on using the switching circuitry112. In one instance, the switching circuitry 112 is a single-use,conductive tape-switch. The instrumentation circuitry 107 may includeone or more light sources, such as a light-emitting diode (LED), controlcircuitry and logic, and one or more photodetectors, such as aphotodiode. The communication device 103 can be any suitable type ofcommunication device, including, but not limited to, a wireless lowenergy radio (examples of which include, but are not limited to, BLE,ANT, Zigbee, etc.). Wireless connection and authentication (whenrequired) between communication devices 116 and 103 can be accomplishedthrough standard pairing methods (i.e., Just Works, etc.) andout-of-band methods, such as Near-Field Communication (NFC),barcode/image scanning, or via an optical link between the opticalsensor 110 and camera (or optical sensor) housed in the computing device105. Depending on the configuration of the medical device 100, thestorage device 115 may comprise, but is not limited to, volatile storage(e.g., random access memory), non-volatile storage (e.g., read-onlymemory), flash memory, or any combination of such memories.

The medical device 100 can be communicatively coupled to a computingdevice 105, such as a smart phone, a tablet computing device, a desktopor laptop computer, a wireless computing and/or data aggregatorappliance device, a bedside monitor, or a similar computing devicethrough a wired or wireless connection. The computing device 105 caninclude a communication device 116 and a storage device 118 connected toa processing device 117. The medical device 100 transmits, via thecommunication device 103, measurement data to the computing device 105(via the communication device 116) to be processed, displayed and/orstored. The measurement data can be used for alarms, for electronicmedical record data transfer, for data sharing, and/or for other uses ofthe data.

The computing device 105 may further include one or more input devices(represented by input device 121) and/or one or more output devices(represented by output device 122). The input and output devices 121,122 are connected to the processing device 117. The input device 121 canbe implemented as any suitable input device, such as a keyboard(physical or virtual), a mouse, a trackball, a microphone (for voicerecognition), an image capture device, and/or a touchscreen or touchdisplay, or any other computer-generated perceptual input information.The output device 122 may be implemented as any suitable output device,such as a display, one or more speakers, and/or a printer, or any othercomputer-generated perceptual output information. In some embodiments,the measurement data or data representative of the measurement data canbe provided to the output device 122. For example, the measurement dataor data representative of the measurement data may be displayed on adisplay.

In some embodiments, the computing device 105 and/or the medical device100 can access an external storage device 119 through one or morenetworks (represented by network 120) to store and/or retrievemeasurement data. In one or more embodiments, the network 120 isillustrative of any suitable type of network, for example, an intranet,and/or a distributed computing network (e.g., the Internet) over whichthe computing device and/or the medical device 100 may communicate withother computing devices.

As will be described in more detail later, the measurement data producedby the medical device 100 can be processed to determine or estimate oneor more physiological parameters (e.g., pulse rate, blood oxygensaturation). As part of the processing, one or more signals areprocessed with a numerical solver device. The numerical solver devicecan be implemented with one or more circuits (circuitry), a softwarealgorithm or program executed by one or more processing devices (e.g.,processing device 102 and/or processing device 117), or a combination ofcircuitry and a software algorithm.

For example, in one embodiment, the storage device 115 in the medicaldevice 100 can include a number of software programs or algorithms anddata files, including a numerical solver device. While executing on theprocessing device 102, the numerical solver device may perform and/orcause to be performed processes including, but not limited to, theaspects as described herein. In another embodiment, the storage device118 in the computing device 105 can include a number of softwareprograms or algorithms and data files, including a numerical solverdevice. While executing on the processing device 117, the numericalsolver device may perform and/or cause to be performed processesincluding, but not limited to, the aspects as described herein. In yetother embodiments, the operations of the numerical solver device aredistributed such that some of the operations are performed by theprocessing device 102 and some of the operations are performed by theprocessing device 117.

FIGS. 2G-2L illustrate example adhesive tape layouts suitable for usewith a medical device. In the figures, each medical device uses adifferent adhesive tape layout, such as those depicted in FIGS. 2G and2H, respectively. Specifically, in the illustrated embodiment, a medicaldevice 203 is attached to a patient's fingertip 202 using a flatadhesive bandage 205 encapsulated in a polytetrafluoroethylene (PTFE)pocket or in an origami made out of biocompatible tape 206, as shown inFIG. 2G. An optical sensor 207 on the underside 208 of the medicaldevice 203 may contact the patient's skin when the underside 208 isadhered to the patient's skin. In some of the many alternativeembodiments, such as those shown in FIGS. 2H through 2L, an adhesivebandage or tape 204 may be used to attach the medical device 203 to ameasurement site.

Small Footprint

Embodiments of the medical device can provide a relatively smallfootprint (size). Among other aspects, a smaller size can require lessmaterial in manufacturing, improved ease of use, less room required forstorage, less costs for transport, and a less intrusive device andinstrument for patients' increased comfort and mobility when using themedical device. In one embodiment, the medical device 100 may include aprinted circuit board (PCB) comprising the processing device 102 with anintegrated communication device 103, a compact integrated circuit thatincludes the instrumentation circuitry 107 for signal conditioning andLED current driving, the power supply 109, and the converter 108. Thepower supply 109 combined with the converter 108 provide the requiredhigher voltage to drive the light sources 113 and/or a photodetector 114of the optical sensor 110. In one embodiment, the converter 108 is asingle DC-DC switched converter, the power supply 109 is a disposablebattery, the light sources 113 are LEDs, and the photodetector 114 is asilicon photodiode.

The processing device 102 and the instrumentation circuitry 107 can bepowered directly by the power supply 109. The optical sensor 110 may beencapsulated with the PCB by any one of a wide variety of suitableapparatus and methods, including (by way of example) by attachingflexible adhesive tapes of various types (optionally combined with PTFE)to the PCB. Persons of ordinary skill in the art will understand thatthe PCB may be rigid or flexible, or be in the form of a substrate wheresome or all the components are die attached and wire bonded to thesubstrate, and encapsulated for protection using epoxy or some otherencapsulation material. Further, the optical sensor 110 may be attachedto a measurement site 111 using any of a wide variety of suitableapparatus and methods, including (by way of example) by using theadhesive tapes that are part of the optical sensor 110 encapsulationstructure (as described herein).

Low Power Consumption

In some aspects, the processing device 102 is a low-power ARM processorwith dual functionality for controlling a wireless low energy radio(communication device 103) and instrumentation circuitry 107. Theoptical sensor 110 can include high efficiency LEDs and at least onesilicon photodiode that are arranged in a reflective configuration suchthat the LEDs and the at least one silicon photodiode are physicallyseparated from each other to minimize the required LED currents andfrontend gains in the instrumentation electronics. The instrumentationcircuitry 107 may have very low bias currents and operate at lowvoltages. In one embodiment, ambient light interferences may be avoidedor at least reduced by modulating and time-multiplexing the LEDs'currents at a higher frequency to shift the spectral content of thegenerated and detected optical signals to a range in the spectrum whereambient light interferences are less likely to occur.

FIG. 3 depicts a distributed system suitable for processing signalsproduced by a medical device and an example modulation scheme that issuitable for use with a medical device. The modulation scheme 300 mayreduce the complexity of the demodulation, decimation, LED currentcalibration, sensor off patient, error handling and alarms, diagnostics,and/or communication algorithms shown in the algorithm block diagram302. Some or all of the blocks in the algorithm block diagram 302 areincluded in a medical device 303. The LED driver algorithms, thefrontend algorithms, and the supervisory algorithms can each be softwareprograms that are stored in the storage device 115.

In the modulation scheme depicted in FIG. 3, each LED (light source 113)is kept turned on for approximately 25% of the modulation time cycle(LED duty cycle). Smaller LED duty cycles can be used to reduce overallpower consumption. The LEDs can be kept turned off for approximately 50%of the modulation time cycle. The intervals where the LEDs are turnedoff can also be increased if the LED duty cycles are to be reduced andif the modulation frequency is kept the same. The two slots 305, 306 inthe waveform represent times when the LEDs are turned off. The two slots305, 306 can be used to probe and cancel the effects of ambient light.Modulation frequencies as low as 1 KHz can be adopted withsignal-to-noise ratio figures similar to medical-grade pulse oximetersin embodiments that perform sophisticated filtering and signalprocessing in the demodulation scheme to recover the optical signalsgenerated by the interplay of the LEDs optical signals and theattenuation caused by the measurement site's blood perfused tissue.

In some embodiments, a distributed computing architecture may be used tocalculate one or more physiological parameters such as blood oxygensaturation (SpO2), a pulse rate (PR), and a perfusion index (PI). Forexample, the SpO2, PR and PI are estimated on a host computing device304 (e.g., a mobile phone or laptop) to increase the battery life of themedical device. In one embodiment, one or more numerical solver devicescan be included in the backend algorithms of the host computing device304. For example, a numerical solver device can be included in theoxygen saturation and pulse rate algorithm and in the perfusion indexalgorithm. In another example, one or more numerical solver devices canbe a separate algorithm that is called by the oxygen saturation andpulse rate algorithm and by the perfusion index algorithm.

In other embodiments, one or more numerical solver devices can beincluded in the medical device 303. For example, one or more numericalsolver devices may be implemented in the frontend algorithms, such as,for example, the demodulation algorithm.

A processing device in the medical device 303 (e.g., processing device102 in FIG. 1) may execute the time critical, high frequency, lowlatency and low complexity tasks. Data processed by the processingdevice in the medical device 303 may be reduced in bandwidth bydecimation algorithms, and sent wirelessly to the host computing device304 (e.g., to a processing device). In one embodiment, the hostcomputing device 304 may execute more complex, high latency tasks tocalculate and continuously display the measurement values for SpO2, PRand PI.

In an example embodiment, the medical device frontend from TexasInstruments (AFE4403) can be used as the instrumentation circuitry 107(FIG. 1). In such embodiments, the medical device frontend may beprogrammed to generate and control directly the required LED modulationscheme without the need for additional resources from the sensorprocessing device 102.

Other example modulation schemes are shown in FIG. 4A. The RED-GREEN-IRModulation scheme and/or the Multi-Wavelength Sequential Modulationscheme can be used with measurement sites that have low perfusion and/orsubject to excessive motion. FIG. 4B and FIG. 4C depict flowcharts ofmethods of determining which modulation scheme to use. FIGS. 4B-4C showexample scenarios where a particular type of modulation can beadvantageous. In the method shown in FIG. 4B, the adopted modulationscheme depends on the aforementioned factors (e.g., low perfusion and/orsubject to excessive motion). Initially, as shown in block 400, adetermination is made as to whether the measurement site has lowperfusion and/or is subject to motion. If not, the process passes toblock 402 where the modulation scheme shown in FIG. 3 can be used. Whenthe measurement site has low perfusion and/or is subject to motion, themethod continues at block 404 where a RED-GREEN-IR Modulation scheme ora Multi-Wavelength Sequential Modulation scheme may be used.

In the method shown in FIG. 4C, a determination is made at block 406 asto whether one or more measurements of other blood parameters are to beobtained or determined. The blood parameters can include, but are notlimited to, glucose, water, and hemoglobin. If one or more measurementsof other blood parameters is to be determined, the process passes toblock 408 where the modulation scheme shown in FIG. 3 or theRED-GREEN-IR Modulation scheme shown in FIG. 4A can be used. If one ormore measurements of other blood parameters will not be determined, themethod continues at block 410 where the Multi-Wavelength Modulationscheme may be used.

For the RED-GREEN-IR Modulation scheme shown in FIG. 4A, green and redLEDs are activated and modulated for a period of time according to theon-off pattern described, and then, the red LED (RED) is replaced withthe near-infrared LED (IR) and also modulated for a period of time. Thissequence of events repeats itself while the measurement site is subjectto motion and/or low perfusion levels. When light in the wavelengthrange between violet and yellow (i.e., between 400 to 590 nmapproximately) is applied to a blood-perfused measurement site, thehigher light scattering and absorption seen in this region, createphotoplethysmographs that are much larger in amplitude when compared tothe ones in the red and near-infrared wavelength regions. Typically, thegreen wavelength is used because LEDs in this range offer goodefficiency and reliability as well as lower cost when compared to otherwavelengths in the violet-yellow range. Also, the optical properties ofblood in the green region are desirable in terms of scattering andabsorption levels. The photoplethysmograph associated with the green LEDcan be used to improve detection of the heart rate and/or the detectionof the red and near-infrared true photoplethysmograph amplitudes andwaveforms, which are required for an accurate measurement of the blood'soxygen saturation under low-perfusion and motion conditions.

The Multi-Wavelength Sequential Modulation scheme shown in FIG. 4A canbe used in some embodiments when the parameters of interest requireother wavelengths in addition to the red and near-infrared LEDs.Examples include the non-invasive measurement of other bloodconstituents (parameters), such as glucose, for diabetes diseasemanagement, water, for body hydration management, total hemoglobin, foranemia and/or blood transfusion management, etc. As shown in FIG. 4A, anumber of light sources of various centroid wavelengths (i.e., λ1, λ2, .. . , λn LEDs) are turned on and off sequentially over time. In the caseof the non-invasive measurement of glucose, multiple LEDs in the rangeof 900 nm to 1700 nm can be adopted. In the case of the non-invasivemeasurement of total hemoglobin and/or water, wavelengths in the rangeof 600 nm to 1350 nm should be sufficient. The spectral ranges definedare sufficient because blood and bloodless components at the measurementsite have spectral features that are typically quite distinctivedepending on the wavelength sub-range under consideration. For instance,water and glucose have higher absorption in the 1550 nm to 1700 nm rangethan the other components, the hemoglobin species have pronouncedfeatures in the 600 nm to 1350 nm, fat has in general pronouncedscattering properties throughout the whole range when compared to otherblood components, and so on and so forth. The modulation schemes shownin FIG. 3 and FIG. 4A can be switched over time depending on theparticular application and/or measurement conditions.

In some embodiments, the method shown in FIG. 4C can be used in amulti-parameter medical device that continuously measures SpO2, PR andPI, using the modulation shown in FIG. 3 and/or the RED-GREEN-IRModulation scheme shown in FIG. 4A. The medical device can performlower-frequency periodic spot-check measurements of other bloodparameters, such as the ones previously mentioned (i.e., glucose, water,etc.) using the Multi-Wavelength Modulation scheme. Such a topology ispossible because typically water, glucose, hemoglobin, etc.concentrations in blood vary slower when compared to SpO2, PR and PI.Because typical measurement periodicity for the said parameters is ingeneral much longer (i.e., once every 30 minutes, once an hour, etc.),the increase in the medical device power consumption is not significant.The additional LEDs and photodetector technologies (i.e., silicon andindium gallium arsenide photodiodes for the 600 nm to 1700 nm wavelengthmeasurement range) required represent small incremental cost andnegligible increase in sensor footprint.

The Multi-Wavelength Modulation scheme shown in FIG. 4A can also be usedto measure SpO2, PR and PI. In this configuration, the red andnear-infrared LEDs are combined with other wavelengths to create “n”photoplethysmographs that can be used to improve SpO2 accuracy or motionperformance. Accuracy is improved at least in part because additionalLEDs throughout the visible and near-infrared range enable estimationalgorithms to counter the optical interference effects of other bloodand bloodless components not needed in the measurement of oxygensaturation, pulse rate and/or perfusion. Operation under motion isimproved because the effects of motion acceleration on the venous andcapillary blood creates optical interferences in the measurement sitethat have distinct morphological features depending on the wavelengthrange, and hence are more likely to be eliminated from thephotoplethysmographs through advanced signal processing such as thenumerical solver device described herein.

Persons of ordinary skill in the art will understand that thewavelengths and other measurements and ranges discussed herein aregenerally intended to be representative of certain embodiments of theinventions, and not as delimiting as to the many ways in which theinventions can be practiced.

As described earlier, a distributed computing architecture may be usedto compute SpO2, PR and PI, where SpO2, PR and PI are estimated on ahost computing device (e.g., host computing device 304 in FIG. 3 andcomputing device 105 in FIG. 1) to increase the medical device's batterylife. The processing device in the medical device (e.g., processingdevice 102 in FIG. 1) may execute the time critical, high frequency, lowlatency and low complexity tasks. Data processed by the processingdevice in the medical device may be reduced in bandwidth by decimationalgorithms, and sent wirelessly to the host computing device. In oneembodiment, one or more processing devices in the host computing device(e.g., processing device 117 in the computing device 105) may executemore complex, high latency tasks to calculate and continuously displaythe measurement values for SpO2, PR and PI.

FIG. 5 is a cross-section view of an example medical device. FIG. 5depicts one of the many ways of fabricating a stack-up of the variouscomponents of a wireless, disposable, continuous medical device 500. APTFE encapsulation pocket or an origami made out of biocompatible tape510 may house the components of the medical device 500. From top-down,the medical device 500 may include: an antenna 509, a battery 508, aprinted circuit board (PCB) 501 and PCB circuitry 502, and an opticalsensor 503. For attachment to a patient's measurement site such as afingertip, the medical device 500 may include a PCB-to-skin adhesivelayer 506. Adhesive layer 505 is made out of electrically conductivetape (such as an isotropically conductive pressure sensitive tape), andadhesive layer 504 contains electrical contacts that (when closed) feedpower to PCB 501. A release liner 507 may be disposed between theadhesive layers 504 and 505, and on adhesive layer 506 such that whenthe release liner is pulled, it exposes the optical sensor 503 and theadhesive layer 506 for attachment to a patient's measurement site, aswell as connecting layers 504 and 505, to power on the medical device.

FIGS. 6A-6C are schematic diagrams illustrating an example medicaldevice. The medical device may include an integrated circuit 602 (FIG.6A) such as the AFE4403 or the AFE4490 circuits by Texas Instruments,including a photodiode frontend, LED drivers, and control logic. Anoptical sensor 603 (FIG. 6A), such as the SFH7050 sensor by OSRAM, mayinclude green, red, and near-infrared LEDs and a silicon photodiode. Themedical device may include a main processing device 601 (FIG. 6B), suchas the ARM Cortex MO processor available from Nordic Semiconductors.Further, the medical device may include a 16 MHz crystal oscillator 605,a 32.768 kHz crystal oscillator 604 (when ANT low-energy radio is used),a 2.45 GHz impedance balloon filter (single to differential) 606, amatching impedance circuit 607, and an antenna 608 (FIG. 6B). A powermanagement circuit of the medical device shown in FIG. 6C may include: aboost converter 621 such as TPS61220 from Texas Instruments, a ferriteinductor 611, boost converter voltage setting resistors 609, 610, debugpads 612 for the main processing device 601, noise rejection pull downresistor 613, battery voltage terminals 614, ON switch pads 615, andvoltages 616, 617, 618, 619, 620 for the main processing device 601(FIG. 6B) and integrated circuits. In one embodiment, the ON switch pads615 are single use pads.

As should be appreciated, the components depicted in FIGS. 6A-6C, andthe corresponding descriptions of FIGS. 6A-6C, are for purposes ofillustration only and are not intended to limit embodiments to aparticular sequence of steps or a particular combination of hardware orsoftware components.

FIG. 7 is a flowchart illustrating an example method of processingmeasurement data received from a medical device. The illustrated methodfits measurement data to a model and based on the model, determines oneor more physiological parameters (e.g., PR, SpO2, PI). Depending on theapplication, the method of FIG. 7 is performed once, or the methodrepeats for a given number of times. For example, with a medical device,the method shown in FIG. 7 can repeat as long as a stream of measurementdata is received. In a non-limited example of a medical device, themethod of FIG. 7 repeats substantially every 0.75 seconds.

Initially, as shown in block 700, a stream of measurement data isreceived. In one embodiment, the stream of measurement data is atime-multiplexed and modulated digital stream of measurement data. In amedical device embodiment, the stream of measurement data represents anysuitable number of measurement samples that are captured by the medicaldevice at a given sampling frequency (e.g., 4 kHz). In one embodiment,the stream of measurement data is captured continuously by the medicaldevice, although other embodiments are not limited to thisimplementation.

The stream of measurement data is then demodulated and filtered at block702 to produce individual data streams for each wavelength channel(e.g., red, infrared, etc.). Any suitable demodulation technique can beused. In a non-limiting example embodiment, a demodulation system caninclude a multi-channel symmetric square wave demodulator deviceoperably connected to a filter device. The filter device can beimplemented as a single stage or a multi-stage filter device. In someembodiments, the demodulator device and/or the filter device performdecimation, where the sampling frequency is reduced to a lower value(e.g., from 4 kHz to 1 kHz, from 1 kHz to 50 Hz) to reduce signalprocessing requirements, wireless bandwidth, and/or power consumption.Additionally or alternatively, the demodulation system and techniquesare capable of removing most or substantially all interference signalswithin a pre-defined continuous frequency range (i.e., 0 Hz to 800 Hz).

In some aspects, each individual data stream is a photoplethysmographdata stream. At block 704, each individual data stream is normalized. Inone embodiment, a log of each data stream is taken and bandpass filteredto produce a photoplethysmograph data stream for each wavelengthchannel.

Next, at block 706, the photoplethysmograph data streams are processedby a numerical solver device to calculate or estimate optimizationvariables that minimize a cost function to produce one or morephotoplethysmograph models. In one embodiment, the photoplethysmographdata streams are processed in data batches of any size that is suitablefor a particular application. For example, with a medical device, thedata batch size can be the equivalent of a few seconds of data (e.g.,250 samples collected over 5 seconds) and updated in real-time everycertain time interval (e.g., 0.75 seconds).

In one aspect, the numerical solver can compare the data streams with aseries of indexed photoplethysmograph models parameterized by theoptimization variables. For example, for each Pulse Rate (PR) value,from 25 to 250 BPM in steps of 1 BPM, the numerical solver devicecalculates values for the optimization variables that minimize a costfunction to produce the best photoplethysmograph model for the givendata streams. In one non-limiting embodiment, the cost function can bedefined by the following equation:

$\begin{matrix}{{{J\left( {x,z} \right)} = {\sum\limits_{i = 1}^{n}{\left( {{z_{i}{Ax}} - b_{i}} \right)^{T}\left( {{z_{i}{Ax}} - b_{i}} \right)}}},} & {{Equation}\mspace{14mu} 1}\end{matrix}$where A∈R^(k×m), k≥m, is a constant matrix, b_(i)∈R^(k)=1, 2, . . . nare constant vectors, x∈R^(m) and z=[z₁ z₂ . . . z_(n)]^(T)∈R^(n) arethe optimization variable vectors, and the T superscript is thetranspose operator.

Each photoplethysmograph model produced based on the numerical solverdevice and its corresponding PR value is considered a data point (pair).As a result, in this example, the photoplethysmograph models are indexedby the PR values. If the cost function is given by Equation 1, then eachphotoplethysmograph model is represented by the vector Ax and scalingfactors z_(i), and the photoplethysmograph data streams are representedby the vectors b_(i). The optimization variables are the vector x andscaling factors z_(i). Each column in Matrix A provides informationregarding the underlying application or phenomenon. In one embodiment,Matrix A is indexed by (function of) the PR values. As a result, theentries in Matrix A change for each PR value, which in turn change theoptimal solutions for x and scaling factors z_(i) that minimize the costfunction in Equation 1.

Next, as shown in block 708, the one or more metrics are computed foreach photoplethysmograph model indexed by a PR value by comparing thephotoplethysmograph models with a reference photoplethysmograph model.The reference photoplethysmograph model represents the best or aselected photoplethysmograph model for a user associated with themeasurement data. In one embodiment, the one or more metrics areassociated with the photoplethysmograph model. Example metrics include,but are not limited to, root mean square accuracy (Arms), correlation,L2 norm, L1 norm, Linf norm, power, correlation, and harmonic andmorphology analysis matching. Because the one or more metrics arecalculated from photoplethysmograph models that are indexed by PRvalues, the one or more metrics are also indexed by the same PR values.

For example, in some embodiments, the one or more computed metrics arecompared with corresponding metrics associated with the referencephotoplethysmograph model (reference metric(s)) to determine how closeor similar the one or more computed metrics are to the correspondingreference metric(s). Additionally or alternatively, the shape of eachphotoplethysmograph model is compared with a shape of the referencephotoplethysmograph model to determine how similar or dissimilar eachphotoplethysmograph model is to the reference photoplethysmograph model.In some embodiments, metrics such as the root mean square accuracy(Arms), correlation, L2 norm, L1 norm, Linf norm, correlation, andharmonic and morphology analysis matching can be used to access thedegree of compliance (shape similarity) between photoplethysmographmodel and reference photoplethysmograph model.

At block 710, an optimal photoplethysmograph model is selected ordetermined for each wavelength channel and one or more values ofinterest are estimated or computed. The values of interest can includevalues of interest for physiological parameter such as SpO2, PR, PI,and/or other physiological parameters of interest. The values ofinterest are computed by applying classification criteria (algorithms)to the computed metrics (i.e., maximum value, minimum value, a ratio ofvalues, linear and non-linear classification algorithms, etc.). Forinstance, the best estimate for PR, for given red and infrared datastreams, may be obtained by picking the PR value that produces thephotoplethysmograph model with the largest normalized power, providedthat the corresponding photoplethysmograph model Arms error value (whencompared to the most current reference photoplethysmograph model) isless than a specified threshold. The best estimate for SpO2 and PI maybe calculated via the scaling factors (red and infrared amplitudes) fromthe photoplethysmograph model that produced the best estimate for PR.

One or more outliers are then removed from the estimated values ofinterest to produce a subset of values of interest. In some embodiments,average estimates of the values of interest are produced at block 712.Any suitable technique can be used to remove the outliers.

The subset of values of interest are then provided to a storage device(e.g., memory) and/or an output device (block 714). For example, the oneor more values of interest can be displayed on a display. Next, as shownin block 716, the reference photoplethysmograph model is updated basedon the subset of values of interest and/or the optimalphotoplethysmograph model (e.g., the associated optimization variables).In one embodiment, the reference photoplethysmograph model is updatedvia an update rule that produces a weighted average of the currentreference photoplethysmograph model and the optimal photoplethysmographmodel.

FIG. 8A depicts a perspective top view of a container that includes adisposable medical device. In some embodiments, the container 800 isused to ship the medical device 100 and/or to sell the medical device100 to distributors and consumers. Any suitable container 800 can beused. One example of a container 800 is a blister package.

The container 800 includes a roll of a biocompatible tape 802 inaddition to the medical device 100. In some embodiments, the container800, or the area inside the tube or tape roll 801, can store a headband,bandage, or other attachment mechanism that allows the user to wrap orcover the medical device when the medical device is attached to theforehead, ear lobe, nose, neck, or other measurement site.

To open the container 800, a tab 804 can be removed or torn off toenable the top portion 806 of the container 800 to be separated from thebottom portion 808 of the container 800. The medical device 100 and thebiocompatible tape 802 can then be removed from the container 800.

FIG. 8B illustrates a bottom view of the container. A label 810 can beaffixed to the bottom portion 808 of the container 800. For example, thelabel 810 can be attached to a bottom lid of the container 800. Inanother embodiment, the label 810 may be included in the container 800but not affixed to the container 800 such that the label 810 isremovable from the container 800. In the illustrated embodiment, thelabel 810 is positioned such that the label 810, or at least anidentifier 812, is visible through the bottom portion 808 of thecontainer.

The identifier 812 can be used to authenticate the medical device 100 toenable the medical device 100 to pair with a host computing device. FIG.9 is a flowchart depicting an example method of generating an identifierfor a medical device. In some instances, the method of FIG. 9 isperformed at a manufacturing site of the medical device or at apackaging site where the medical device is packaged in the container(e.g., container 800 in FIG. 8A).

Initially, as shown in block 900, the serial number of the medicaldevice is obtained. In one embodiment, the serial number is anon-erasable serial number that is stored in a storage device (e.g.,storage device 115 in FIG. 1) in the medical device. The serial numberis read out of the storage device and a credential is computed based onthe serial number (block 902). A non-limiting example of a credential isa hash number.

In some embodiments, different or additional data can be used to computethe credential. For example, in a non-limiting embodiment, thecredential (e.g., hash number) can be based on the serial number of themedical device, a lot number of the medical device, a version number ofthe medical device, a model number of the medical device, an expirationdate of the medical device, or various combinations of the serialnumber, lot number, version number, and model number. In otherembodiments, the credential can be computed using other data associatedwith the medical device 100.

Any suitable process or function can be used to compute the credential.For example, when the credential is a hash number, the algorithm that isused to compute the hash number may be a non-standard and customizedalgorithm for computing the hash number. Since the hash number is basedon data associated with the medical device itself (e.g., the serialnumber, an expiration date, etc.), the hash number uniquely identifiesthe medical device.

Next, as shown in block 904, an identifier is generated for the medicaldevice 100 and produced on a label for the container. Any suitableidentifier can be used. In one embodiment, the identifier is a bar codethat includes at least the hash number and the corresponding datarequired to compute the said hash number. In some embodiments, theidentifier can include additional data, such as the serial number of themedical device, the version number of the medical device, the modelnumber of the medical device, the expiration date of the medical device,or combinations thereof.

After an identifier is generated for the medical device 100, softwarecode or firmware is stored in a storage device 115 in the medical device100 at block 906 to enable the medical device to function once it isactivated by the user. After the software or firmware code is programmed(stored) into the medical device 100, a read-back protection isactivated in the storage device 115 or processing device 102 to preventusers and unauthorized persons or systems from accessing the softwarecode or firmware (block 906).

FIG. 10 is a flowchart illustrating an example method of authenticatinga medical device once it is activated by the user using the identifierproduced in FIG. 9. In one embodiment, the operations shown in FIG. 10are performed at a host computing device. Initially, as shown in block1000, the label with the identifier is scanned by the host computingdevice. FIGS. 11A-11B depicts one example technique for scanning a labelthat includes an identifier for the medical device. In FIG. 11A, themedical device 100 is attached to a user 1102 (e.g., a finger) via theadhesive surface on the medical device 100. Additionally, as shown inFIG. 11A, an attachment mechanism (e.g., a bandage or the biocompatibletape 802 in FIG. 8) is wrapped around the medical device and the finger.The medical device 100 is turned on so that the medical device 100 isready to connect to the host computing device 1104.

The host computing device 1104 includes an application 1106 thatreceives and processes data from the medical device 100. The application1106 includes a scanning operation that is used to scan the identifier1110 on the label 1108. As discussed earlier, the label 1108 includesthe identifier 1110.

In FIG. 11B, the label 1108 is positioned adjacent the host computingdevice 1104 for the scanning operation. For example, the label 1108 ispositioned in front of an image capture device (e.g., input device 121in FIG. 1) in, or connected to, the host computing device 1104. In someembodiments, an image of the label 1108 is displayed on a display 1112(e.g., output device 122) of the host computing device 1104. The imagecapture device captures an image of the label 1108. The host computingdevice 1104 processes the image and the identifier 1110 to obtain atleast the original hash number (computed in FIG. 9, block 902) and thedata used to calculate the original hash number. As discussed earlier,the original has number can be computed based on the serial number, aversion number, a lot number, an expiration date, a model number, and/orcombinations thereof.

Returning to FIG. 10, the host computing device calculates anauthentication hash number from the data in the identifier (block 1002).At block 1004, the host computing device compares the calculatedauthentication hash number to the original hash number (computed in FIG.9) stored in the identifier that was scanned in block 1000. Adetermination is made at block 1006 as to whether the calculatedauthentication hash number matches the original hash number. If the twohash numbers do not match, the process passes to block 1008 whereauthentication of the medical device fails and a wireless connectionbetween the medical device and the host computing device is notattempted. In some embodiments, the user can be informed of the failedauthentication using any suitable output device, such as, for example, atext message displayed on a display or a verbal message output by aspeaker.

When the calculated authentication hash number matches the original hashnumber at block 1006, the method continues at block 1010 where the hostcomputing device computes a first pairing credential (e.g., hash number)based on data in the identifier 1110 that is also stored at the medicaldevice. For example, in one embodiment, the serial number of the medicaldevice included in the identifier 1110 is also stored in a storagedevice of the medical device. The first pairing credential is thencomputed based on the serial number. In other embodiments, other data inthe identifier 1110, such as the lot number or the version number, maybe stored at the medical device. In such embodiments, the other data canbe used to determine a first pairing credential (e.g., hash number).

The host computing device then transmits the first pairing credential tothe medical device at block 1012. The host computing device can transmitthe first pairing credential wirelessly to the medical device using anysuitable wireless communication protocol (e.g., Zigbee, BLE, ANT).

Next, as shown in block 1014, the medical device computes a secondpairing credential (e.g., hash number) based on the data (e.g., theserial number) stored in a storage device of the medical device. Adetermination is made at block 1016 as to whether the first and thesecond pairing credentials match. If the two pairing credentials do notmatch, the process passes to block 1018 where the medical device is notpaired with the host computing device. When the first and the secondpairing credentials match, the method continues at block 1020 where themedical device is authenticated and the medical device connects or pairswith the host computing device. In some embodiments, the user can beinformed of the successful authentication using any suitable outputdevice, such as, for example, a text message displayed on a display or averbal message output by a speaker.

FIGS. 12A-12C illustrate an example method for activating a medicaldevice. FIG. 12A is a bottom view of the medical device. The medicaldevice 100 includes a removable first tab 1202 (indicated by “1”). Thefirst tab 1202 is removed from the medical device 100. For example, thefirst tab 1202 can be a pull tab that is removed by pulling the tab 1202away from the medical device 100.

FIG. 12B is a top view of the medical device 100 after the first tab1202 has been removed. The medical device 100 includes a removablesecond tab 1204. A user presses on area 1206 (indicated by a circle)until an optical indicator turns on (see optical indicator 1208 in FIG.12C). By pressing on area 1206, a user may assist in forming anelectrical connection between a conductive contact and the two contactpads on the PCB 2402 (see e.g., contact pads 615 in FIGS. 6C and 35A),where the electrical connection activates the medical device 100. Theilluminated optical indicator 1208 indicates the medical device 100 isturned on and activated.

FIG. 12C is a top view of the medical device 100 after the opticalindicator 1208 is illuminated. The removable second tab 1204 is thenremoved from the medical device 100 in order to expose an adhesive tape1210 on the surface 1212 of the medical device 100 (see FIG. 12D). Forexample, the second tab 1204 can be pull tab that is removed by pullingthe tab 1204 away from the medical device 100.

FIG. 12D is an isometric view of the medical device 100 after the secondtab 1204 has been removed. The optical indicator 1208 remainsilluminated and indicates the medical device 100 is ready for attachmentto a user.

FIG. 13 illustrates an example method of attaching the medical device toa user. Initially, the medical device 100 is positioned at a measurementsite of the user with the optical indicator 1208 facing toward themeasurement site. For example, as shown in FIG. 13, the medical device100 is positioned on a user's index finger 1300 with the opticalindicator facing area 1302 on the fingertip of the finger 1300 and theadhesive tape 1210 attached to the fingertip. An optional tape 1304,such as biocompatible tape 802 in FIG. 8, is wrapped around thefingertip and the medical device 100 to improve the optical compliancebetween the medical device 100 and the finger 1300 (e.g., themeasurement site) and/or to protect the medical device 100.

FIG. 14 depicts two state diagrams of the medical device and a hostcomputing device operably connected and in communication using awireless connection. Any suitable wireless protocol can be used for thewireless connection, such as BLE and Zigbee protocols. State diagram1400 represents example firmware that can run in a medical device. Statediagram 1402 represents an example Application software that may run ina host computing device. The state diagrams 1400, 1402 describe thearchitecture and operation of the firmware in the medical device and theApplication software on the host computing device.

The following sequence of events in the illustrated state diagram 1400of the medical device can occur in one embodiment, after the medicaldevice is initially activated 1404. Once initialization is complete1406, the medical device enters in low-power mode state 1408, and waitsfor the host computing device to send the authentication and pairingcredentials (e.g., the authentication and pairing hash numbers). Theauthentication process described in conjunction with FIG. 10 can be partof the credential exchange process that occurs during device pairing.Once pairing is complete 1410, the medical device enters an idle state1412 and waits for events, such as data acquisition and processing, datatransmission, and supervisory tasks. As will be described in more detaillater, the medical device is reset and re-initialized in the event of ahardware/software (HW/SW) failure or exception.

The following sequence of events in state diagram 1402 of theApplication software may occur in one embodiment, after the Applicationbegins executing 1414 and pre-initialization 1416 is completed. The hostcomputing device, through the Application software, is in a “notconnected” state 1418 and will search wirelessly for a medical device toconnect to. When pairing is complete 1420 and the host computing deviceis connected to the medical device 1422, the Application softwareperforms post-initialization 1424 and enters an idle state 1426. Thehost computing device, through the Application software, will then waitfor events, such as data processing, data reception, storage, andtransmission tasks. In the event of a lost wireless connection with themedical device, the Application software on the host computing deviceresumes a search for the medical device to reestablish the lost wirelessconnection.

The following provides a description of the firmware state diagram 1400of the medical device.

Power On state 1404: Tests the operation readiness of the medicaldevice. In case of an error, the firmware resets the medical device andstarts over. If the error persists, the firmware transitions to an idlestate. If the medical device does not respond in a given period of timeto the host computing device, the lack of response can be considered anexception or fault.

Low-Power state 1408: Upon successful initialization, the medical deviceenters into a Low Power state until the wireless connection isestablished, so as to maximize battery life.

Idle State 1412: The medical device enters into an Idle State once thewireless connection is established with the host computing device. Allapplication tasks may follow an event-driven model in order to minimizepower consumption and remove the need for a Real-Time Operating System(RTOS) framework, so as to reduce the amount of memory and computationaloverhead.

AFE State 1428: A processing device in the medical device maycommunicate with an Analog Front End (AFE) by means of an interface,such as a Serial Peripheral Interface (SPI) bus. The communicationbetween the AFE and the processing device is driven by hardwareinterruption events 1430, so as to minimize power consumption and enablelow-latency response.

TX State 1432: The processing device in the medical device can send datapackages (e.g., continuously) to the host computing device using aprotocol, such as a UART/Serial Port Emulation over BLE protocol stack.The data packages may be sent periodically or at select times via timerexpiration events 1434.

Supervisory State 1436: The firmware of the medical deviceasynchronously monitors the AFE, the optical sensor, and the batteryvoltage for correct and timely exception/error handling. The AFE, theoptical sensor, and the battery voltage are periodically monitored viatimer expiration events 1438.

Reset State 1440: The processing device of the medical device handlessoftware and hardware recoverable faults, and/or exceptions by means ofa timer 1442 that (if not reset from time to time) will reset andre-initialize 1444 the medical device.

The following provides a description of the Application software statediagram 1402 of the host computing device.

Application Startup State 1414: The Application software may display astartup screen that displays or provides information about the medicaldevice and/or the Application software. Additionally or alternatively,the Application software can initialize all services and components usedto connect and receive real-time data from the medical device.

Not Connected State 1418: The Application software searches and connectsto the medical device, provided that the user inputs the properauthentication and pairing credentials, including, in some embodiments,a wireless password for the wireless connection. The Applicationsoftware remains in the “not connected” state 1418 until a connectionwith the medical device is established. The Application software canre-establish a connection with the medical device whenever theconnection is lost 1446 due to recoverable exceptions and/or faults.

Connected State 1422: The Application software initializes all servicesand components used to process, visualize, and/or store real-time datareceived from the medical device. In some embodiments, the Applicationsoftware can generate warnings and alarms when required.

Idle State 1426: The Application software can be placed in an Idle Stateafter a wireless connection is established with the medical device torelease host computing device resources and/or reduce power consumption.

UI State 1448: The Application software can update measurements andtrends, issues alarms and warnings, and may be responsive to UserInterface (UI) requests whenever needed. The UI may be updatedperiodically via timer expiration events 1450.

RX State 1452: The Application software can receive data packages (e.g.,continuously or at select times) from the medical device using aprotocol, such as, for example, an UART/Serial Port Emulation over a BLEprotocol stack. The data packages are processed to extract/estimateparameters of interest. Each data package can be received and processedperiodically by means of timer expiration events 1454.

Data Storage State 1456: The Application software can store thereal-time data received from the medical device using any suitablestorage technique, such as, for example, log files, databases and/ortables. Additionally or alternatively, the Application software maystore data that is processed by the Application software itself. Datastorage may occur periodically via timer expiration events 1458.

FIGS. 15-19 illustrate example user interface views of the Applicationsoftware that can be displayed on the host computing device. The dashedline in FIGS. 15, 16, 18, and 19 represents a host computing device andthe user interface view is displayed on a display device (e.g., atouchscreen). The dashed line in FIG. 17 represents a display screen ofa display device (e.g., a display screen on a touchscreen).

As described earlier, the host computing device is connected wirelesslyto a medical device. The medical device, in combination with the hostcomputing device, together form a pulse oximetry system. FIG. 15 depictsan example “Start” user interface view 1500 that can be displayed on thehost computing device, where a user can scan 1502 the identifier on thelabel (e.g., the barcode), display the barcode and/or other dataassociated with the medical device 1504 (e.g., serial number, modelnumber, etc.), enter or scan a patient's or user's ID 1506, and/or entera patient's or user's gender 1508 and Date of Birth 1510.

FIG. 16 illustrates a measurement user interface view that can includemeasurement types, values, gauges, and/or waveforms. The example userinterface view 1600 includes three measurement types 1602, 1604, 1606.Other embodiments can display one or more measurement types. Themeasurement type 1602 displays in real-time the user's oxygen saturation(SpO2) as a numerical value 1608. Additionally or alternatively, in someembodiments, a measurement gauge 1610 can display the numerical value ina graphical form, such as a horizontal bar (shown in FIG. 16) or a piechart.

The measurement gauge type 1604 displays in real-time the user's pulserate (PR) as a numerical value 1612. Additionally or alternatively, insome embodiments, a measurement gauge 1614 may display the numericalvalue in a graphical form (e.g., a horizontal bar).

The measurement type 1606 displays in real-time the user's perfusionindex (PI) as a numerical value 1616. Additionally or alternatively, insome embodiments, a measurement gauge 1618 may display the numericalvalue in a graphical form (e.g., a horizontal bar).

In some embodiments, the measurement user interface view 1600 can alsodisplay in real-time the user's photoplethysmographs 1620. Themeasurement user interface view 1600 may further display a fuel gauge1622 that displays the battery power levels for the medical device, andan icon 1624 that enables or provides access to one or more menus (e.g.,an Options Menu) and/or other functionalities. For example, from theOptions Menu, a user can access the “Start” screen 1500, a “Share Data”screen (see FIG. 19), and/or a “Settings” screen (see FIG. 18), as wellas other screens that may provide additional functionalities.

FIG. 17 depicts a measurement user interface view that provides all thefunctionalities from the measurement user interface view 1600 of FIG. 16as well as trend data functionalities. The measurement type 1700 (shownin boldface font) indicates that a SpO2 trend data 1702 is displayed inthe measurement user interface view 1704 (e.g., on the right side of themeasurement user interface view 1704). The user can select themeasurement types 1706, 1708 to switch the corresponding trend datadisplayed on the right side of the measurement user interface view 1704.For example, in one embodiment, the user may touch a particularmeasurement type to select the measurement type when the measurementuser interface view 1704 is presented on a touchscreen.

FIG. 18 illustrates an example settings user interface view. In someembodiments, the settings user interface view can be accessed via theicon 1624 in FIG. 16. The settings user interface view 1800 allows auser to set various settings for the Application software, including themeasurement types, values, waveforms, and gauges. For example, an amountof time for a trend data chart can be set using setting 1802. In anon-limiting embodiment, the amount of time options that can be selectedinclude 2, 5, 10, 30 or 60 minutes.

A trend data storage period may be set using setting 1804. Examplestorage options include, but are not limited to, the last 12, 24, 36 or48 hours. In some embodiments, the trend data storage period is arolling time period once trend data for the amount of time is stored.For example, once trend data for 12 hours is stored, new trend data isstored in a storage device and the oldest trend data is deleted from thestorage device.

Settings associated with an audible alarm may be set via the settingsuser interface view 1800. The audible alarm can be enabled or disabledusing setting 1806. An alarm silence time period in which the audiblealarm is temporarily silenced may be set using setting 1808. Forexample, when an alarm is provided, a user can select any element in theuser interface to silence the alarm for a limited time period. Examplealarm silence time periods include 30, 60, 90, and 120 seconds. Othertime periods can be used for the trend data chart 1802, the trend datastorage 1804, and the silence time period 1808.

In some embodiments, upper and lower alarm limits for select measurementtypes can be set via the settings user interface view 1800. When ameasurement is equal to or greater than an upper limit, an alarm can beprovided. Similarly, an alarm may be provided when a measurement equalsor is less than the lower limit. In the illustrated embodiment, upperand lower alarm limits can be set for the SpO2 and the PR measurements1812, 1814. In a non-limiting example, each alarm limit can be specifiedusing a sliding switch. Other embodiments can use a different mechanismto specify each alarm limit, such as a dialog box or a pull-down menu.The setting 1816 may be used to set or enable a waveform storage timeperiod (e.g., the last 12 hours).

FIG. 19 depicts an example share data user interface view. In someembodiments, the share data user interface view can be accessed via theicon 1624 in FIG. 16. Using the share data user interface view 1900, auser can choose the data type 1902 to be shared with a third partydevice (e.g., trends or waveforms). The user may select a “Share” inputbutton 1904 when the user is ready to share the data with the thirdparty device. When the “Share” input button 1904 selected, a shareoperation transfers data to the third party device via one or moresharing methods or applications (e.g., email, text message, cloud, etc.)that are available in the host computing device and/or in the medicaldevice. In some embodiments, the data types to be shared with a thirdparty device may include one or more of PDF reports, EMR records, trenddata, waveform data, hardware and/or software diagnostics data, and thelike.

FIG. 20A is a flowchart depicting an example method of operating analarm system. Initially, a determination is made at block 2000 as towhether the medical device is out of range of the host computing deviceor if the wireless connection between the medical device and the hostcomputing device is unreliable (e.g., slow data transmission rates orrepeated disconnections). If so, the process passes to block 2002 whereoptionally an audible alarm is produced by the host computing device. Insome embodiments, the audible alarm can be output by the medical deviceinstead of, or in addition to, the host computing device.

Additionally or alternatively, one or more visible alerts can beproduced at the host computing device at block 2004. For example, one ormore elements in the user interface of the Application can be changedand/or emphasized. For example, a measurement type, gauge, or value canchange color, blink on and off, and/or change font or font style (e.g.,bold, italicize). In some embodiments, haptic feedback, a text message,and/or one or more audible sounds can be produced by the host computingdevice in addition to, or as an alternative to, the visual alerts. Themethod then returns to block 2000.

When the medical device is within range of the host computing device andthe wireless connection between the medical device and the hostcomputing device is reliable, a determination can be made at block 2006as to whether the medical device is not attached to the user. The phrase“not attached” can refer to situations where the medical device is notattached to a user, or the medical device is attached to a user but isnot transmitting valid physiological data obtained from the user to thehost computing device. For example, when the medical device is withinrange of the host computing device and the wireless connection isreliable, but the host computing device is not receiving any validphysiological data from the medical device, a determination can be madethat the medical device is not attached to a user. The method continuesat optional block 2002 and block 2004 when the medical device is notattached to a measurement site.

When the medical device is attached to the user, the process continuesat block 2008 where a determination is made as to whether the amount ofpower or energy stored on the battery in the medical device is low. Forexample, the amount of power stored on the battery can be low when theamount of power falls below a threshold value. If so, the methodcontinues at optional block 2002 and block 2004.

When the amount of power or energy stored on the battery in the medicaldevice is not low, the process passes to block 2010 where adetermination is made as to whether the amount of power or energy storedon the battery in the host computing device is low. For example, theamount of power stored on the battery can be low when the amount ofpower falls below a threshold value. If so, the method continues atblock 2012 where the host computing device provides one or more warningsor alerts. In a non-limiting example, the host computing device candisplay one or more text messages, output audible alerts or sounds,provide haptic feedback, and the like.

When the determination at block 2010 is that the amount of power orenergy stored on the battery in the host computing device is not low, orafter block 2012, the process continues at block 2014 where adetermination is made as to whether a measurement of blood oxygensaturation SpO2 is equal to or greater than the upper limit set for theaudible alarm (e.g., SpO2 alarm limits 1812 in FIG. 18). When the SpO2measurement equals or exceeds the upper limit, the method passes toblock 2002 where an optional audible alert is provided. Additionally oralternatively, visible alerts can be produced by the host computingdevice at block 2016. For example, the SpO2 measurement type, gauge, orvalue can change color, blink on and off, and/or change font or fontstyle (e.g., bold, italicize). In some embodiments, a text message canbe displayed by the host computing device in addition to, or as analternative to, the visual alerts. The process then continues at block2020.

When the SpO2 measurement equals or is less than the upper limit, themethod passes to block 2018 where a determination is made as whether ameasurement of blood oxygen saturation SpO2 is equal to or less than thelower limit set for the audible alarm (e.g., SpO2 alarm limits 1812 inFIG. 18). When the SpO2 measurement equals or is less than the lowerlimit, the method continues at block 2002 where an optional audiblealert is provided. Additionally or alternatively, visible alerts can beproduced by the host computing device at block 2016. For example, TheSpO2 measurement type, gauge, or value can change color, blink on andoff, and/or change font or font style (e.g., bold, italicize). In someembodiments, haptic feedback, a text message, and/or one or more audiblesounds can be provided by the host computing device in addition to, oras an alternative to, the visual alerts. The process then passes toblock 2020.

When the SpO2 measurement equals or is greater than the lower limit, themethod continues at block 2020 where a determination is made as whethera measurement of the pulse rate PR is equal to or greater than the upperlimit set for the audible alarm (e.g., PR alarm limits 1814 in FIG. 18).When the PR measurement equals or exceeds the upper limit, the methodpasses to block 2002 where an optional audible alert is provided.Additionally or alternatively, visible alerts can be produced by thehost computing device at block 2022. For example, The PR measurementtype, gauge, or value can change color, blink on and off, and/or changefont or font style (e.g., bold, italicize). In some embodiments, hapticfeedback, a text message, and/or one or more audible sounds can beoutput by the host computing device in addition to, or as an alternativeto, the visual alerts. The process then returns to block 2000.

When the PR measurement equals or is less than the upper limit, themethod passes to block 2024 where a determination is made as whether thePR measurement is equal to or less than the lower limit set for theaudible alarm (e.g., PR alarm limits 1814 in FIG. 18). When the PRmeasurement equals or is less than the lower limit, the method continuesat block 2002 where an optional audible alert is provided. Additionallyor alternatively, visible alerts (and/or other types of alerts) can beproduced by the host computing device at block 2022. After block 2022 isperformed, or when the PR measurement equals or is greater than thelower limit, the method returns to block 2000.

Other embodiments can implement the method shown in FIG. 20A differentlyby adding, modifying, omitting, or re-arranging the blocks. For example,blocks 2010 and 2012 may be omitted in other embodiments. Additionallyor alternatively, the decisions at blocks 2014, 2018, 2020, 2024 candetermine whether the SpO2 or the PR measurements are greater than theassociated upper limit or less than the associated lower limit (e.g.,alarm and/or alert not generated when a measurement is equal to theupper or lower limit).

FIG. 20B is a flowchart illustrating an example method of producing anaudible alarm. The operations shown in FIG. 20B can be performed inblock 2002 in FIG. 20A. Initially, a determination is made at block 2026as to whether the Application software on the host computing device isin background mode. In some instances, the host computing device can runmultiple applications in addition to the Application software associatedwith the medical device. The Application software is running in thebackground (“background mode”) when another application is running inthe foreground. In some embodiments, when the Application software isrunning in background mode, the process continues at block 2028 wherethe audible alarm is provided. Thus, in some embodiments, the audiblealarm is provided regardless of whether the Application software isrunning in background or foreground mode. In other embodiments, anaudible alarm may not be produced by the host computing device when theApplication software is running in background mode. In such embodiments,the method can begin at block 2030 or block 2032.

When the Application software is not running in background mode (e.g.,is running in foreground mode), the method passes to block 2030 where adetermination is made as to whether the host computing device iscurrently in a low power mode. For example, the host computing devicemay be in a sleep mode, an airplane mode, a silent mode, or anotherpower saving mode. In some embodiments, when the host computing deviceis in a low power mode, the process continues at block 2028 where theaudible alarm is provided. Thus, in some embodiments, the audible alarmis provided regardless of whether the host computing device is in, ornot in, a low power state. In other embodiments, an audible alarm maynot be produced when the host computing device is operating in a lowpower state. In such embodiments, the method can begin at block 2032.

When the host is not in a low power mode at block 2030, the processcontinues at block 2032 where a determination is made as to whether theaudible alarm is enabled. If not, the method passes to block 2004, 2016,or 2022 depending on the state of the method. When the audible alarm isenabled, the process continues at block 2034 where a determination ismade as to whether the alarm silence is activated. If the alarm silenceis activated (i.e., not timed out), the method passes to block 2004,2016, or 2022 (FIG. 20A) depending on the state of the method. When thealarm silence is not activated, the audible alarm is generated at block2028.

Other embodiments can implement the method shown in FIG. 20B differentlyby adding, modifying, omitting, or re-arranging the blocks. For example,blocks 2026 and 2030 may be omitted in other embodiments. Additionallyor alternatively, block 2028 may be performed before block 2034 and ifthe alarm silence has not timed out, the process may wait at block 2034until the alarm silence has timed out. When the alarm silence times outat block 2034, the method can return to block 2028 and blocks 2028 and2034 may repeat until the alarm is turned off.

FIG. 21 illustrates a block diagram of a first configuration for amedical device and a host computing device. In the illustratedembodiment, a medical device 2100 includes a processing device 2102operably connected to a storage device 2104. The storage device 2104stores a biosensing algorithm 2106 and an encryption algorithm 2108 thatare each executed by the processing device 2102. The biosensingalgorithm 2106 processes data collected by the medical device to producehealth related measurement results that are in a form that is meaningfulor understandable to various users (e.g., individuals wearing themedical device, caregivers, health care professionals). The healthrelated measurement results are encrypted using the encryption algorithm2108 and transmitted 2110 to the host computing device 2112.

The host computing device 2112 includes a processing device 2114operably connected to a storage device 2116 and an output device 2118.The storage device 2116 stores a decryption algorithm 2120 that isexecuted by the processing device 2114 to decrypt the encrypted healthrelated measurement results. The processing device 2114 provides thedecrypted health related measurement results to the output device 2118.For example, the host computing device can display the results on adisplay screen (e.g., a touchscreen).

One limitation with the configuration in FIG. 21 is that unauthorizedpersons or systems (e.g., a hacker) can obtain the health relatedmeasurement results during transmission 2110 from the medical device2100 to the host computing device 2112. Although the health relatedmeasurement results are encrypted during transmission 2110, anunauthorized person or system may be able to decrypt some or all of thehealth related measurement results. Since the health related measurementresults are in a form that is meaningful or understandable to users, thehealth related measurement results are also meaningful or understandableto the unauthorized person or system.

Embodiments described in conjunction with FIGS. 22 and 23 provideimproved security for the health related measurement results. In FIGS.22 and 23, the biosensing algorithm that processes the data collected bythe medical device is grouped into two parts, Part 1 and Part 2. Part 1process the data collected by the medical device and producesintermediate results. However, the intermediate results are not in aform that is meaningful or understandable to users. Part 2 processes theintermediate results to produce health related measurement results in aform that is meaningful or understandable to users. For example, Part 1of the biosensing algorithm may produce data that relates to one or morewaveforms (e.g., photoplethysmographs) or trend data, and Part 2 canproduce the numerical values for one or more measurement types (e.g.,SpO2, PR, and/or PI).

FIG. 22 depicts a block diagram of a second configuration for a medicaldevice and a host computing device. In the illustrated embodiment, amedical device 2200 includes a processing device 2102 operably connectedto a storage device 2104. The storage device 2104 stores Part 1 of abiosensing algorithm 2202 and an encryption algorithm 2108. Part 1 ofthe biosensing algorithm 2202 and the encryption algorithm 2108 are eachexecuted by the processing device 2102. Part 1 of the biosensingalgorithm 2202 processes data collected by the medical device to produceintermediate health related measurement results that are in a form thatis not meaningful or understandable to various users. The intermediatehealth related measurement results are encrypted using the encryptionalgorithm 2108 and transmitted 2110 to the host computing device 2204.

The host computing device 2204 includes a processing device 2114operably connected to a storage device 2116 and an output device 2118.The storage device 2116 stores Part 2 of the biosensing algorithm 2206and the decryption algorithm 2120. Part 2 of the biosensing algorithmand the decryption algorithm are each executed by the processing device2114. The encrypted intermediate health related measurement results aredecrypted using the decryption algorithm 2120. The decryptedintermediate health related measurement results are then processed usingPart 2 of the biosensing algorithm 2206 to produce health relatedmeasurement results that are in a form that is understandable ormeaningful to various users. The processing device 2114 provides thehealth related measurement results to the output device 2118. Forexample, the host computing device can display the results on a displayscreen (e.g., a touchscreen).

FIG. 23 illustrates a block diagram of a third configuration for amedical device and a host computing device. In this representativeembodiment, the intermediate health related measurement data is notencrypted or decrypted by the medical device and the host computingdevice, respectively. A medical device 2300 includes a processing device2102 operably connected to a storage device 2104. The storage device2104 stores Part 1 of a biosensing algorithm 2202. Part 1 of thebiosensing algorithm 2202 is executed by the processing device 2102 toprocesses data collected by the medical device and produce intermediatehealth related measurement results that are in a form that is notmeaningful or understandable to various users. The intermediate healthrelated measurement results are transmitted 2110 to the host computingdevice 2302.

The host computing device 2302 includes a processing device 2114operably connected to a storage device 2116 and an output device 2118.The storage device 2116 stores Part 2 of the biosensing algorithm 2206.Part 2 of the biosensing algorithm is executed by the processing device2114 to process the intermediate health related measurement results andproduce health related measurement results that are in a form that isunderstandable or meaningful to various users. The processing device2114 provides the health related measurement results to the outputdevice 2118. For example, the host computing device can display theresults on a display screen (e.g., a touchscreen).

In the configurations of FIGS. 22 and 23, the intermediate healthrelated measurement data transmitted to the host computing device is ina form that is not understandable or meaningful to both users,unauthorized persons, and unauthorized systems. An unauthorized personor system must be knowledgeable about both Part 1 and Part 2 of thebiosensing algorithm to process and understand the intermediate healthrelated measurement data.

FIG. 24 illustrates example components of a medical device. Thecomponents include a battery 2400, a printed circuit board (PCB) 2402that includes electronic circuitry that performs the functionalities ofthe medical device, a tape encapsulation assembly 2404, the removablefirst tab 1202, a product label 2408, and the removable second tab 1204.The battery 2400 can be implemented with any suitable battery. Thebattery 2400 includes a first terminal 2412 (e.g., positive terminal)and a second terminal 2414 (e.g., negative terminal). In one embodiment,the battery 2400 is a lithium manganese dioxide (Li—MnO2)non-rechargeable battery. The Li—MnO2 battery can provide high energydensity (about 250 Wh/kg), a wide operating temperature range (−5 to 60Celsius), and/or a long shelf life due to very low rate ofself-discharge. In some instances, the Li—MnO2 battery can withstandhigh pulse current transients that typically occur in wireless radiocircuitries. In other embodiments, different battery technologies (suchas silver oxide, etc.) can be used. For example, a silver oxide batteryhaving comparable energy density, temperature range, shelf life, and/ormaximum electrical current can be used.

The PCB 2402 may be rigid or flexible, or be in the form of a substrate,where some or all the components are die attached and wire bonded to thesubstrate. In one aspect, the PCB 2402 is encapsulated for protectionusing epoxy or some other encapsulation material. In a non-limitingembodiment, the electronic schematics shown in FIGS. 6A-6C can beimplemented on the PCB 2402. A layout with the processing device 601,the integrated circuit 602, the antenna 608, the ferrite inductor 611,the boost converter 621, and two contact pads 2416, 2418 is shown inFIG. 24. The optical sensor 603 is attached on the bottom side of thePCB 2402 (see FIG. 25B).

The tape encapsulation assembly 2404 may be a single coated foam medicaltape with a biocompatible foam backing. The tape encapsulation assembly2404 can include a conductive contact (see 2808 in FIG. 33) thatoperates as a one-time ON switch to activate the medical device when auser removes the removable first tab 1202. The tape encapsulationassembly 2404 further includes a release liner 2420. FIGS. 26A-34Billustrate a method for constructing the biocompatible adhesive tapeencapsulation assembly 2404.

The second tab 1204 is removable, and when removed, exposes a portion ofthe tape encapsulation assembly 2404 that can be used to attach themedical device to a measurement site on a user. FIG. 38 depicts detailedcross-sectional views of an example second tab 1204.

FIGS. 25A-39B depict an example method of assembling a medical device.FIGS. 25A-25B illustrate a method of attaching the battery 2400 to thePCB 2402 and folding the PCB 2402 and the battery 2400. The terminals2412, 2414 of the battery 2400 are electrically connected to the contactpads 2416, 2418 of the PCB 2402 to form a PCB-battery assembly 2500. Forexample, the terminals 2412, 2414 can be soldered to the contact pads2416, 2418. The terminal 2412 can be aligned with the ferrite inductor611 when the terminals 2412, 2414 are electrically connected to thecontact pads 2416, 2418.

In one embodiment, the battery 2400 is positioned bottom side up 2502(e.g., label side down) when the terminals 2412, 2414 are electricallyconnected to the contact pads 2416, 2418. FIG. 25B depicts the battery2400 folded over the PCB 2402. The terminals 2412, 2414 are bent suchthat the bottom side 2502 of the battery 2400 is positioned over the PCB2402 and the top 2504 of the battery 2400 is visible (see FIG. 25C). Ina non-limiting embodiment, the PCB 2402 can be held in a fixed positionwhile the battery 2400 is pushed or rotated over the PCB 2402 so as tosuperpose the battery 2400 on the PCB 2402 (e.g., the battery 2400 isstacked over the PCB 2402).

FIGS. 26A-26C illustrate an example tape encapsulation component that ispart of the tape encapsulation assembly. FIG. 26A depicts a top view ofthe tape encapsulation component 2600. The tape encapsulation component2600 includes a sensor window 2602 and a removable cover 2604. As willbe described in more detail later, the optical sensor is aligned withthe sensor window 2602.

FIG. 26B shows a bottom view of the tape encapsulation component. Thetape encapsulation component 2600 includes a contact opening 2606 thatextends through the tape encapsulation component 2600. As will bedescribed in more detail later, the contact opening 2606 enables theremovable first tab 1202 to be passed through the contact opening 2606and extend to out of the opposite side of the tape encapsulationcomponent 2600.

FIG. 26C illustrates a cross-sectional view of the tape encapsulationcomponent taken along line C-C in FIG. 26B. The bottom surface of thetape encapsulation component 2600 includes the release liner 2420 thatis disposed under an adhesive layer 2608. The adhesive layer 2608 ispositioned under a backing layer 2610. In one embodiment, the backinglayer 2610 comprises a foam backing layer. The tape encapsulationcomponent 2600 may be manufactured by die cutting a biocompatiblesingle-coated foam medical tape, although other embodiments are notlimited to this implementation.

FIG. 27 depicts the top view of the tape encapsulation component withthe removable cover removed. In one embodiment, the removable cover 2604is kiss cut in the release liner 2420. When the removable cover 2604 isremoved, a portion of the adhesive layer 2608 of the tape encapsulationcomponent 2600 is exposed. Any suitable technique can be used to removethe removable cover 2604. In one embodiment, tongs or a pincer tool(e.g., a tweezer) is used to remove the cover 2604.

FIG. 28 illustrates an example third tab. The third tab 2800 can be usedto transfer a conductive adhesive layer 2808 to the exposed portion ofthe adhesive layer 2608. The third tab 2800 includes a liner component2802 and a liner tab 2804. A portion of the liner component 2802includes the liner tab 2804 disposed under the conductive adhesive layer2808. The conductive adhesive layer 2808 is positioned under a releaseliner 2806. In an example embodiment, the conductive adhesive layer 2808is formed with conductive microfibers disposed on a conductive layer.Other embodiments can use a different type of a conductive adhesivelayer.

FIG. 29 depicts an example technique for transferring the conductiveadhesive layer of the third tab to the tape encapsulation component. Thethird tab 2800 is aligned with the exposed portion of the adhesive layer2608. In one embodiment, a gap is created between the edges of thecontact opening 2606 and the end of the third tab 2800 (shown inenlarged view 3000 in FIG. 30). The third tab 2800 is then lightlypressed onto the exposed portion of the adhesive layer 2608 and removedto transfer the conductive adhesive layer 2808 to the exposed portion ofthe adhesive layer 2608. FIG. 30 illustrates the tape encapsulationcomponent after the conductive adhesive layer is transferred to theexposed portion of the adhesive layer in the tape encapsulationcomponent. As shown in the enlarged view 3000, the conductive adhesivelayer 2808 is positioned on the adhesive layer 2608 such that theadhesive layer 2808 is disposed along one or more edges of theconductive adhesive layer 2608, leaving a gap between adhesive layer2808 and contact opening 2606.

FIG. 31 depicts an example removable first tab. The removable first tab1202 includes a liner layer 3100. A label 3102 is disposed under theliner layer 3100 at a first end 3108 of the removable first tab 1202. Atthe other end 3110 of the removable first tab 1202 the liner layer 3100is positioned under an adhesive layer 3104. The adhesive layer isdisposed under a support layer 3106. In a non-limiting embodiment, thesurface of liner layer 3100 touching adhesive layer 3104 is a non-tackysilicon layer. The adhesive layer 3104 keeps the support layer 3106attached to the liner layer 3100. The support layer 3106 is a metallicfoil layer (e.g., a copper foil). The adhesive layer 3104 and themetallic foil layer 3106 provide additional mechanical strength to theend 3110 of the removable first tab 1202 to assist in extending the end3110 into the contact opening 2606 of the tape encapsulation component2600. FIG. 32 illustrates the removable first tab inserted into thecontact opening of the tape encapsulation component.

FIG. 33 depicts a perspective top view of the tape encapsulationcomponent. The end 3110 of the removable first tab 1202 extends throughthe contact opening and forms a tab 3300. When the removable first tab1202 is inserted into the contact opening, the removable first tab 1202is positioned such that the support layer 3106 is adjacent the exposedconductive adhesive layer 2808. The support layer 3106 and the adhesivelayer 3104 are removed from the tab 3300, which leaves the liner layer3100 with non-tacky silicon surface facing the exposed conductiveadhesive layer 2808.

FIG. 34A illustrates the liner layer 3100 folded over the conductiveadhesive layer. The liner layer 3100 is used to electrically isolate andprotect the conductive adhesive layer 2808. The combination of theremovable first tab 1202 attached to the tape encapsulation component2600 produces the tape encapsulation assembly 2404. FIG. 34B depicts abottom view of the tape encapsulation assembly. The removable first tab1202 is bended and folded onto the backing layer 2610 of the tapeencapsulation assembly 2404. In the illustrated embodiment, theremovable first tab 1202 is folded over the backing layer 2610 with thenumber “1” facing the backing layer 2610.

Once the tape encapsulation assembly 2404 is constructed, thePCB-battery assembly 2500 is attached to the tape encapsulation assembly2404 (see FIG. 35A). Initially, the release liner 2420 is removed toexpose the adhesive layer 2608. The PCB-battery assembly 2500 ispositioned on the adhesive layer 2608 such that the optical sensor 603on the PCB (shown on the left) is positioned over the sensor window2602. The light source(s) 113 emit light through the sensor window 2602and the photodetector(s) 114 receives reflected light through the sensorwindow 2602. Additionally, the (ON switch) contact pads 615 (see e.g.,FIGS. 6C and 35A) on the PCB 2402 are aligned with the liner layer 3100positioned over the conductive adhesive layer 2808. FIG. 35B is a sideview showing the PCB-battery assembly 2500 attached to the tapeencapsulation assembly 2404.

After the PCB-battery assembly 2500 is attached to the tapeencapsulation assembly 2404, the tape encapsulation assembly 2404 iswrapped around the PCB-battery assembly 2500. FIGS. 36A-36E illustratean example method of folding the tape encapsulation assembly around thePCB-battery assembly. As shown in FIG. 36A, the tape encapsulationassembly 2404 includes four tabs 3600, 3602, 3604, 3606. The surface ofthe four tabs 3600, 3602, 3604, 3606 is the adhesive layer 2608.

Initially, a first tab 3600 is folded over the PCB-battery assembly 2500(FIG. 36B). A second tab 3602 is then folded over the PCB-batteryassembly 2500 and the first tab 3600 (FIG. 36C). A third tab 3604 isfolded over the PCB-battery assembly 2500 and the first and the secondtabs 3600, 3602 (FIG. 36D). The removable first tab 1202 is visible(e.g., the “1”) when the third tab 3604 is folded. Finally, a fourth tab3606 is folded over the PCB-battery assembly 2500 and the first and thesecond tabs 3600, 3602 (FIG. 36E).

FIGS. 37A-37B illustrate an example method of attaching the removablesecond tab and the product label to the medical device. A liner (notshown) is removed from the product label 2408 to expose an adhesivesurface on the underside of the product label 2408. The adhesive surfaceis then affixed to a bottom surface of the medical device (see FIG.37B). Additionally, a liner layer (see 3806 in FIG. 38) is removed fromthe removable second tab 1204 to expose an adhesive layer (e.g., 3814 inFIG. 38) on the underside of the second tab 1204. The adhesive layer isthen affixed to a top surface of the medical device. As shown in FIG.37A, area 1206 (indicated by a circle) of the second tab 1204 is aligned(e.g., center aligned) with the end of the removable first tab 1202 (theend of the tab farthest from the number “1”).

When constructed, the medical device 100 includes the PCB-batteryassembly 2500, the tape encapsulation assembly 2404 wrapped around thePCB-battery assembly 2500, and the second removable tab 1204 positionedon a surface of the tape encapsulation assembly 2404. The secondremovable tab 1204 includes a two-sided adhesive layer that provides anadhesive layer (e.g., layer 1210 in FIG. 12D) on a surface of themedical device 100 when the second removable tab 1204 is removed fromthe medical device 100. The PCB 2402 includes the electronic circuitrythat performs the functionalities of the medical device 100, includingan optical sensor 603 that comprises at least one light source to emitlight towards a measurement site of a user and at least onephotodetector to receive light returned from the measurement site (e.g.,113 and 114 in FIG. 1). The PCB 2402 also includes at least one contactpad comprising an ON switch of the medical device (e.g., contact pad 615in FIG. 35A). A battery 2400 is electrically attached to the PCB 2402.The tape encapsulation assembly 2404 includes a sensor window 2602positioned over the optical sensor 603, and a contact opening 2606extending through a tape encapsulation component 2600 for receiving afirst removable tab 1202. The first removable tab 1202 includes a linerlayer portion (e.g., tab 3300) disposed on a first surface of the tapeencapsulation component 2600 covering the contact pad or pads on the PCB2402 and a tab portion (e.g., pull-tab of 1202) disposed on an oppositesecond surface of the tape encapsulation component 2600. The liner layerportion (e.g., tab 3300) is positioned between the at least one contactpad (e.g., 615 in FIG. 35A) on the PCB 2402 and the conductive tape 2808in the tape encapsulation component 2600.

FIG. 38 shows a cross-sectional view of an example removable second tab1204. The second tab 1204 includes a first section 3800 and a secondsection 3802. The first section 3800 is formed with a first adhesivelayer 3810 disposed between a first liner layer 3804 and a carrier layer3812 and a second adhesive layer 3814 positioned between the carrierlayer 3812 and a second liner 3806. The second section 3802 is formedwith the first liner layer 3804 and the second liner layer 3806. A gap(e.g., an air gap) is positioned between the first liner layer 3804 andthe second liner layer 3806. When the removable second tab 1204 isremoved from the medical device 100, the adhesive layer 3810 remains onthe top surface of the medical device 100. The adhesive layer 3810 isused to attach the medical device to the measurement site of the user(e.g., to a fingertip of the user).

FIGS. 39A-39B depict a method of packaging the medical device in acontainer. As shown in FIG. 39A, the medical device 100 is positioned ina first molded area 3900 of the top portion 806 of the container 800(FIG. 8) and a tape 1304 (e.g., biocompatible tape 802 in FIG. 8), isdisposed in a second molded area 3902 of the top portion 806 of thecontainer 800. In the illustrated embodiment, the second removable tab1204 is visible when the medical device 100 is in the first molded area3900, although this is not required. The label 810 (FIG. 8) is placedover the medical device 100 and the tape 1304. In the illustratedembodiment, the identifier 812 will be visible when the bottom portion808 of the container 800 is attached to the top portion 806.

In another embodiment, the steps to assemble the tape encapsulationassembly 2404 can be modified by incorporating the conductive tape 2808(FIG. 30) during the lamination and die cutting processes of tapeencapsulation assembly 2404. In this way, the steps shown in FIGS.29-30, as well as the removable third tab 2800, are eliminated becausethe conductive tape 2808 is included in the tape encapsulation assembly2404. This can reduce the cost to manufacture the tape encapsulationassembly 2404.

In addition, to further reduce the manufacturing costs (i.e., tooling,labor) of the tape encapsulation assembly 2404, the release liner 2420can be kiss cut to adhesive foam, and divided into multiple parts thatcan be more easily peeled off to facilitate the removal of the releaseliner 2420 and removable cover 2604 from the encapsulation assembly 2404in the assembling process.

FIGS. 40A-40B illustrate different configurations of a printed circuitboard of a medical device. A measurement site 4000 of a user is shown inFIGS. 40A-40B with a gradient filling. The darker region 4002 representstissue having a higher peripheral blood circulation (dermis), or higherblood perfusion. The lighter region 4004, closer to the optical sensor603, represents tissue having a lower peripheral blood circulation(epidermis), or lower blood perfusion. In FIG. 40A, the surface 4006 ofa PCB 4008 (e.g., PCB 2402 in FIG. 24) in which the optical sensor 603is attached to is flat. When the medical device is attached to themeasurement site 4000, additional placement pressure may be needed toimprove the optical compliance of the optical sensor 603 and the bloodperfused tissue. This can be accomplished by using any suitabletechnique. For example, as described earlier, a tape 1304 (FIG. 13) maybe wrapped around the medical device and the measurement site 4000.Additionally, an adhesive bandage can be applied over the medical device100 and the measurement site 4000.

FIG. 40B depicts the surface 4010 of a PCB 4012 as a convex surface.When the surface 4010 is a convex surface, attaching the medical deviceto the measurement site 4000 with the tape 1304 creates additionalplacement pressure on the tissue around the location of the opticalsensor 603, given that the convex surface bulges out and compresses thetissue. This improves the optical compliance of the optical sensor 603and the measurement site 4000, as well as increases peripheral bloodcirculation around the location of the optical sensor 603. However, inother embodiments, the use of the tape 1304 or another attachmentmechanism to attach the medical device to the measurement site 4000 isoptional or unnecessary based on the convex surface, and only anadhesive layer (such as adhesive layer 1210 in FIG. 12D or 3814 in FIG.38) that attaches the convex surface to the measurement site may besufficient.

In one embodiment, the medical device, the host computing device, andassociated methods and apparatuses described herein can represent aclinical-grade pulse oximetry system. FIG. 41 depicts example technicalspecifications of the medical device when used in combination with ahost computing device. Other embodiments are not limited to any of thespecifications shown in FIG. 41.

In one aspect, the example specifications 4100 can be obtained by designand through biocompatibility, EMC and electrical safety, environmental,bench, and clinical tests. A pulse oximetry system, for instance, istypically certified to comply with several electrical equipment safetystandards, electromagnetic compatibility, and FCC standards. Examplestandards may include, but are not limited to: (i) IEC 60601-1-2:2014Medical Electrical Equipment—Part 1-2: General requirements for basicsafety and essential performance—Collateral Standard: ElectromagneticCompatibility—Requirements and Test. Safety Requirements for ElectricalEquipment for Measurement, Control and Laboratory Use—Part 1: GeneralRequirements; (ii) ANSI/AAMI ES 60601-1:2005/® 2012 Medical electricalequipment—Part 1: General requirement for basic safety and essentialperformance; (iii) 47 CFR Part 15 Subpart B Class B Devices andInnovation, Science; (iv) FCC Part 15, Subpart C and IC RSS-247, Issue1, May 2015; etc.

The intended use 4102 can indicate uses such as measuring and displayingfunctional oxygen saturation of arterial hemoglobin (SpO2), pulse rate(PR), and perfusion rate (PI) of adult and pediatric patients. The pulseoximetry system can be intended for continuous monitoring of patientsduring non-motion and motion, and/or under well-perfused orpoorly-perfused conditions. Example intended environments of use can behospitals, clinics, doctor's offices, and domestic/residential settings.

A clinical-grade pulse oximetry system is commonly subjected to clinicaltesting to certify whether the pulse oximetry system meets the intendeduse 4102. For instance, in the case of a SpO2 accuracy clinical studyrecognized by the Food and Drug Administration (FDA), the pulse oximetrysystem may be tested in accordance to Code of Federal Regulations (CFR)for Non-Significant Risk (NSR) investigational studies, following ISO14155:2011 as appropriate, and the pulse oximetry guidelines of ISO80601-2-61:2011 applicable sections, and Pulse Oximeters—PremarketNotifications Submissions [510(k)s] Guidance For Industry and Food andDrug Administration Staff (issued: Mar. 4, 2013). The purpose of such aclinical study is to evaluate the SpO2 accuracy and performance duringdesaturations with medical devices placed on human subjects (fingers,forehead, temple, ear, etc.) over the range of 70-100% SaO2, arterialblood samples, assessed by CO-Oximetry. The objective is to show theSpO2 accuracy performance of the pulse oximetry system under test.Typically, a population of a given number of subjects (e.g., at leastten healthy adult subjects (male and female)), ranging in pigmentationfrom light to dark is enrolled into such a desaturation study. Duringthe clinical tests, each subject is in a reclined position and connectedto a breathing circuit, for administering medical grade oxygen andnitrogen. The gas flow delivery is adjusted for subject comfort. The gasmixture is controlled to various levels of induced hypoxia resulting instable oxygen saturation plateaus between 100% and 70% SaO2. Arterialblood samples are drawn during simultaneous data collection from thepulse oximetry system under test. The arterial blood samples areimmediately analyzed by Reference CO-Oximetry providing functional SaO2for the basis of the SpO2 accuracy comparison.

FIG. 42 depicts an example scatter plot 4200 and an example Bland-Altmanplot 4202 illustrating a typical SpO2 clinical performance for areflectance-based pulse oximetry system in the 70-100% SaO2 range. Theperformance metrics 4204 are in general the Accuracy Root Mean Square(Arms), bias, linear regression, correlation, etc. computed over anumber of paired samples (SaO2, SpO2). For the plots depicted in FIG.42, nine hundred and forty-three (943) paired samples, evenly spacedover the 70-100% SaO2 range, were used to compute the metrics 4204.

There are clinical and non-clinical applications where users or patientsare given a high oxygen concentration by means of nasal cannula orfacemask, or inside a hyperbaric chamber. These clinical andnon-clinical applications are generally referred to as oxygen therapy.Oxygen therapy is the use of oxygen as a medical or wellness treatment,and is applied to carbon monoxide toxicity treatment, headachetreatment, oxygen concentration supply during anesthesia procedures, andtreatment of COPD (cystic fibrosis, etc.) in patients with chronicallylow oxygen saturation. Aviators may use a nasal oxygen cannula or wearan oxygen facemask when piloting airplanes with non-pressurized cabinsat high altitudes, or during emergencies in order to keep their oxygensaturation at acceptable levels. Athletes may use nasal oxygen cannulasin order to increase performance or stay for a period of time inpressurized oxygen chambers in order to recover more quickly afterworkouts.

Typically, medical devices are calibrated via aforementioned clinicalstudies, where adult patients are subjected to oxygen desaturations overthe range of 70-100% SaO2. These patients are typically healthy adultswith normal cardiorespiratory systems. Typically, health adult patientswill have a measured SaO2 of 97-100% at normal arterial oxygen partialpressure. However, patients still have a percentage of hemoglobin withsome of their oxygen-binding sites still empty at normal arterial oxygenpartial pressure. This implies that, if such patients or users areexposed to a higher concentration of oxygen (such as during oxygentherapy), additional hemoglobin sites will bind to oxygen molecules.However, this increase cannot be captured by conventional medicaldevices because they are calibrated to measure 100% SpO2 at normalarterial oxygen partial pressures. Higher values are typically truncatedto 100%, because the clinical community and regulatory agencies haveadopted the convention that SpO2 should be limited to 100%, since it isa saturation (concentration) measure. What may be missed is the factthat the 100% saturation value is the result of instrument calibrationby means of desaturation studies, and is applicable to patients andusers with normal cardiorespiratory systems and not subjected to oxygentherapy. For patients under oxygen therapy, the ability to read oxygensaturation values higher than 100% is very useful, because it may guidephysicians and/or caregivers in terms of oxygen partial pressuresettings to be administered to a particular patient (based on SpO2readings above 100%), and also to serve as a metric for treatment ofpatients with compromised cardiorespiratory systems (under oxygentherapy).

Co-oximeters (such as the ABL90 FLEX from Radiometer) provide a range ofindication for SaO2 (e.g., the arterial oxygen saturation in the bloodmeasured by a co-oximeter) above 100% (102% for the ABL90 FLEX).Typically, the user has the option to activate the “Out-of-rangesuppression” option and prevent the co-oximeter from reporting valueshigher than 100%. These in-vitro instruments have SaO2 accuracy betterthan 1%. The range of indication above 100% is built-in so as to accountfor measurement errors, as well as to provide clinicians with SaO2reading values above 100% for patients under oxygen therapy. Theinconvenience of such in-vitro instruments (co-oximeters) has to do withtheir inability to provide continuous measurements, as well as the needfor arterial blood samples. Therefore, a non-invasive pulse oximetrysystem, such as the medical device disclosed herein operating incombination with a host computing device that can also monitor SpO2continuously for values above 100%, can be invaluable in clinicalsettings where oxygen therapy is required.

FIG. 43 illustrates experimental points (circles) of a typicalcalibration curve (calcurve) 4300 for a pulse oximetry system. FIG. 43maps optical ratios (red over infrared) produced by the pulse oximetrysystem into SpO2 values. Such a calcurve is usually obtainedexperimentally by means of clinical studies, such as the onesaforementioned, where patients are subjected to oxygen desaturations, orvia optical and physiological modeling using photon-diffusion methods(e.g., Boltzmann's Transport Equation), or via a combination of modelingand experimental data. To enable a medical device to measure and displaySpO2 readings above 100%, the calcurve is extrapolated for SaO2 valuesabove 100%. In the case of this particular experimental calcurve, ared-over-infrared ratio of 0.42 corresponds to 100% SpO2. To extrapolatethe calcurve, a curve can be fit to the experimental points and then,the resulting curve's expression can be used to extrapolate forred-over-infrared ratios below 0.42 (i.e., SpO2 values above 100%). FIG.43 depicts a dashed line 4302 representing a smooth extrapolation afterthe experimental data (circles) are fit to a quadratic polynomial. Insome embodiments, the resulting calcurve polynomial is defined by thefollowing equation:y=−16.79x ²−8.19x+106.43,  Equation 2where x is the red-over-infrared ratio value, and y is the SpO2 value.The “red-over-infrared” ratio not necessarily is obtained or calculatedby dividing two quantities (the red photoplethysmograph over theinfrared photoplethysmograph). Because of numerical stability, noise,and interferences, the division may be replaced with iterative methodsthat find the best linear relation between the two quantities ofinterest. The calculated linear relation will be an estimate for theratio and can be used as a value for x in Equation 2. The“red-over-infrared” ratio can also represent more complex ratiometricrelations between red and infrared photoplethysmographs, and alsocalculated through iterative methods.

Other fittings such as cubic, exponential, etc. can be used to yieldsimilar results. In addition, constrained optimization (fitting)combined with photon-diffusion models can be applied to find anextrapolated curve that satisfies both the calcurve experimental (model)data and the hill's equation (with a cubic term for better accuracy,such as the one disclosed by John W. Severinghaus, in Simple, AccurateEquations for Human Blood 02 Dissociation Computations. J. Appl.Physiol: Respirat. Environ. Exercise Physiol. 46(3):599-602, 1979.Revisions, 1999, 2002, 2007) for a given nominal partial pressure ofoxygen. FIG. 43 also depicts a magnified view 4304 of the extrapolatedSpO2 calcurve 4302.

In terms of displaying SpO2 for values above 100%, the pulse oximetrysystem can offer the same option (“Out-of-range suppression”) as the oneavailable in conventional in-vitro co-oximeters. FIG. 44 depicts ameasurement user interface view of an Application software that can bedisplayed on a host computing device. The SpO2 measurement type 4400displays a numerical value 4202 of 102.3%. Note that a tenth place valuewas added to the numerical value 4402 (when SpO2 is greater than 100%),so as to give clinicians higher measurement granularity, and tocompensate for the smaller dynamic range for SpO2 values above 100%.

FIG. 45 illustrates an example settings user interface view of anApplication software that can be displayed on a host computing device.The user interface view 4500 includes a setting 4502 for “SpO2out-of-range suppression”. This setting provides a clinician with theoption to display (or not display) SpO2 values above 100%. The dashedline in FIGS. 44 and 45 represents a host computing device and the userinterface view is displayed on a display device (e.g., a touchscreen).

Returning to FIG. 41, the measurement ranges for SpO2 are shown with the“SpO2 out-of-range suppression” enabled 4104 and disabled 4106. In oneembodiment, the maximum value of the extended SpO2 range can be 107%,which can be obtained by rounding up the SpO2 value computed from theextended calcurve 4102 (FIG. 41) for a red-over-infrared ratio equals tozero. FIG. 48 shows an example method for providing SpO2 values over100%.

Another aspect of implementing an extrapolated SpO2 calcurve 4102 in amagnified view 4104 (see FIG. 41) relates to the recommendationsdescribed in ISO 80601-2-61:2011, the standard for basic safety andessential performance of pulse oximeter equipment. According to ISO80601-2-61:2011 (section EE.2.3.4 Data analysis), an invasive controlleddesaturation study data analysis should be performed as follows: “forpulse oximeter monitors that place an upper limit on displayed SpO2(e.g. 99% or 100%), a means that does not bias the Arms result should beused. EXAMPLE 1—Include only observations where SpO2 readings are lessthan the upper display limit; EXAMPLE 2—Statistically down-weight thosevalues with SpO2=100% (e.g. treat observations of 100% as censored, asis done in the analysis of survival data); EXAMPLE 3—Configure thedata-collection system to record values of SpO2>100%.”

Therefore, “EXAMPLE 3” enables SpO2 data collected above 100% by thepulse oximetry system under test (during a controlled desaturationclinical study) to be used to compute its SpO2 Arms accuracy. No specialconsiderations or exclusions, such as in “EXAMPLE 1” and “EXAMPLE 2”,are needed. “EXAMPLE 3” is enabled by means of an extrapolated SpO2calcurve 4102 (FIG. 41), where the “SpO2 Out-of-Range Suppression”setting is to be disabled.

There are other pulse oximetry solutions that display ad hoc proprietaryindexes to monitor patients under oxygen therapy. In theseimplementations, indexes typically vary from zero to one, where the zerovalue corresponds to an arbitrary lower limit, and one to an arbitraryupper limit. This approach can be confusing, and not very practical forclinicians. Clinicians are typically trained to interpret values of SpO2in the normal range and unit (scale). Displaying SpO2 values above 100%,in the same scale as the values of SpO2 in the normal range (0-100%), isnot only natural, but also enables physicians and other health careproviders to use their clinical experience (as far as interpreting SpO2readings in the standard scale) to make more accurate clinical decisionson patients under oxygen therapy. The use of an index is not based onscientific principles. It can be a strategy to enable medical devicemanufacturers to claim monitoring capabilities during oxygen therapywithout providing accuracy claims based on scientific methods. Inaddition, because indexes use unit-less scales, manufacturers have thefreedom to disclose measurement principles that are in line with theirstrategy, and not necessarily in agreement with scientific methods andprinciples. The extrapolated SpO2 calcurve, such as the calcurve 4102,is a model-based and data-based approach to measure and display SpO2values above 100% from patients under oxygen therapy, and provides ascientific-based alternative to arbitrary and ad hoc indexes currentlyavailable in the marketplace.

Some of the features for a particular embodiment of a clinical-gradepulse oximetry system, with associated methods and apparatuses disclosedherein, can be described as follows ((1) through (5)):

(1) System components: The clinical-grade pulse oximetry system iscomprised of two components:

-   -   1. A wireless, continuous, fully disposable, single-use medical        device (e.g., medical device 100).    -   2. An Application software installed in a host computing device        (e.g., host computing device 105).        The Application software controls the operation of the host        computing device, so as to enable wireless connection via        low-energy wireless protocol with the medical device 100, and        provides user graphical interface, data storage and management        interface, and sound interface for alarms/warnings. In some        embodiments, for safety and effectiveness, the medical device        100 can only connect and communicate to a host computing device        that has the Application software installed and running. No        other wireless products or devices may be able to make a        wireless connection to the medical device 100

(2) Wireless communication: The purpose of wireless data transferbetween the medical device and the host computing device is to enablethe monitoring (e.g., continuous monitoring) of SpO2, PR, and PI, thegeneration of alarms (e.g., visual and audible alarms), and datastorage. In this particular embodiment, the medical device does notpossess a user interface, input/output devices (i.e., display, speaker,keyboard), or any long-term data storage capability. The medical devicecontrols the electronics in the medical device so as to collecthigh-fidelity optical data continuously from the red and infraredregions, process the data to produce waveforms and diagnostics, and sendall the acquired and processed real-time data wirelessly andcontinuously to the host computing device (e.g., the Applicationsoftware). The host computing device then calculates SpO2, PR, and PImeasurements (e.g., continuously and in real-time) from the receiveddata. In one embodiment, the host computing device calculates SpO2, PR,and PI measurements according to the method described in conjunctionwith FIG. 7. Each real-time data package sent wirelessly by the medicaldevice and received by the host computing device is time stamped, andcan be also saved to a database that logs waveforms and diagnosticsparameters (i.e., LED currents, electronic gains, ambient lightintensity, battery voltage, device temperature, etc.). The wirelessthroughput (bandwidth) can be as low as 450 bytes per second. This canmake the wireless communication between the medical device and the hostcomputing device reliable. In some embodiments, the wireless real-timetransfer of waveforms (or data associated with the waveforms) can occursimultaneously with the wireless real-time transfer of diagnosticsparameters. The waveforms sent to the host computing device have asampling rate that ensures appropriate bandwidth (e.g., 25 Hz), so as tokeep a high-fidelity representation of the photoplethysmographs that areprocessed, displayed, and stored by the host computing device. All theother measurements and diagnostics can be updated at a samplingfrequency as low as 1 or 2 Hz. This is sufficient to capture fasttransients related to the real-time monitoring of SpO2, PR, and PImeasurements and diagnostics. The Application software running on thehost computing device measures wireless data integrity in real-time.Because the data is time stamped, any transmission delays that may occurduring operation cause the Application software to issue one or morealarms (e.g., audible and visual alarms) at the host computing device(or on any other device operably connected to the host computing device)to inform or alert the user. However, the low data throughput (450 bytesper second) can cause such delay events to be rare, provided that theseparation distance between the medical device and the host computingdevice is within the wireless range (e.g., spherical radius ≤10 meters).In some instances, wireless data buffering can be kept to a minimum(e.g., around one tenth of a second) to enable reliable and real-timedata transmission between the medical device and the host computingdevice.

(3) Alarm system: To alert users to abnormal conditions and/or warnings,the clinical-grade pulse oximetry system can provide the following alarmfeatures:

-   -   1. SpO2 and PR upper and lower limit alarms: When SpO2 or PR        value crosses an alarm limit, the corresponding gauge is        highlighted (e.g., turns red and blinks), and an alarm (e.g.,        audible alarm) is issued to alert user. The SpO2 and PR alarm        limits are set by the user.    -   2. Silence alarm activation: Once an alarm is activated, the        user has the option to silence the alarm momentarily by touching        the affected measurement type, gauge, or numerical value (e.g.,        the highlighted measurement type, gauge, numerical value)        displayed on the screen of the host computing device. The user        can set the alarm silence duration using the settings user        interface (e.g., FIG. 18).    -   3. Off patient alarm: The clinical-grade pulse oximetry system        can have one or more algorithms capable of detecting whenever        the medical device has been removed from the patient. This        information triggers one or more alarms (e.g., audible and/or        visual alarms) at the host computing device or any device        operably connected to the host computing device.    -   4. Out of range alarm: The Application software issues one or        more alarms (e.g., visual and/or audible alarms) whenever the        medical device is out of range from the host computing device.    -   5. Low battery alarms: Once the non-rechargeable battery of the        medical device is discharged, the Application software issues        one or more alarms (e.g., visual and/or audible alarms). The        host computing device can also produce multiple warnings and        notifications for the user when the battery capacity of the host        computing device drops below a certain threshold (e.g., 20%).    -   6. Alarms while the Application software is in background mode:        The host computing device can run multiple applications in        addition to the Application software. When the Application        software is in background mode, with another application running        in the foreground, one or more alarms (e.g., audible alarms) are        still issued normally and whenever required by the Application        software.    -   7. Alarms while the host computing device is in low power mode,        airplane mode, and silent mode: In some host computing devices        (e.g., iOS devices, Android devices, etc.), to increase battery        life as well disable audio and wireless radios whenever        necessary, several operation modes are available to the user.        One or more alarms can be issued normally and whenever required        regardless of the operation mode. In the case of airplane mode,        because the wireless radios are disabled, the Application        software may always issue one or more alarms to alert user

(4) Single Application mode: There are clinical applications where it isdesirable to have the host computing device restricted to a singleApplication (i.e., the pulse oximetry system Application software), withhardware buttons and the icon 1642 (FIG. 16) disabled, so as to preventunauthorized users from disabling alarms permanently, or from changingthe Application settings. In such instances, the host computing devicefunctions like a dedicated medical device monitor. With the icon 1642disabled, unauthorized users cannot change (disable) alarm settings. Inone embodiment, the Application software can be designed to be compliantwith Apple's iOS™ “Guided Access” mode. The Guided Access modetemporarily restricts an iOS™ device (host computing device) to a singleApplication, and lets the user control which Application features areavailable. The following describes example default behavior of anApplication during a Guided Access section:

-   -   1. Application termination is disabled: User needs to enter        Guided Access password to exit Guided Access mode to terminate        the Application.    -   2. Side drawer menu (icon 1642 in FIG. 16) is disabled: User        needs to enter Guided Access password to exit Guided Access mode        in order to make changes in the Application settings.    -   3. Portrait and landscape views enabled: User is allowed to        change from portrait to landscape mode without authentication.        The switching between portrait and landscape views, and        vice-versa can be deactivated by just disabling “Motion” in the        iOS™ Guided Access Options menu.    -   4. Hardware buttons disabled (i.e., volume, sleep/wake, etc.):        User is required to enter Guided Access password in order to        enable the hardware buttons.    -   5. User can silence alarms temporarily by taping on gauge        (screen) of affected parameter (i.e., SpO2 or PR): However,        alarms (e.g., audible and/or visual) will be enabled upon        silence time interval expiration. Silence activation can also be        disabled during a Guided Access session, by just disabling        “Touch” in the iOS™ Guided Access Options menu.

(5) Mobile Device Management (MDM): In some organizations, such ashospitals and clinics, a plurality of medical devices (e.g., pulseoximetry systems) may be deployed. In such situations, it can beconvenient and practical to have a MDM framework that manages over theair (remotely) the pulse oximetry systems. The Application software canbe designed to be compatible with commercial MDM frameworks. Thisenables organizations to manage Application software distribution,configuration, settings, and data flow in a centralized fashion, such asfor alarm systems, where alarm events (e.g., SpO2 and PR upper and lowerlimits, off patient, device out of range, low battery, etc. eventalarms) from each pulse oximetry system are relayed to the appropriatehospital areas and/or caregivers. MDM frameworks can simplify andstandardize the management and operation of a plurality of hostcomputing devices working in combination with a plurality of medicaldevices, so as to form a network of pulse oximetry systems such as theones described herein.

FIG. 46 shows a first example of a Mobile Device Management system. Oneor more MDM computing devices (represented by MDM computing device 4600)run and/or manage the Application software 4602 as well as program andconfigure host computing devices and/or medical devices. Multiplemedical devices 100A, 100B, . . . , 100N transmit and receive data fromthe MDM computing device 4600 via network 4604. The network 4604represents one or more intranet networks and/or internet networks(wireless and/or wired). Multiple host computing devices 4606A, 4606B, .. . , 4606N transmit and receive data from MDM computing device 4600 vianetwork 4608. The network 4608 represents one or more intranet networksand/or internet networks (wireless and/or wired). The network 4604 andthe network 4608 can be the same network(s) or different network(s). Insome embodiments, the MDM computing device 4600 acts as an agent thatmanages the Application (“App”) 4602 software distribution,configuration, and settings on host and/or medical devices, and dataflow from medical and/or host computing devices in a centralizedfashion.

In some embodiments, the MDM computing device 4600, the medical devices100A, 100B, . . . , 100N, and/or the host computing devices 4606A,4606B, . . . , 4606N store data in one or more storage devices(represented by storage device 4610).

FIG. 47 depicts a second example MDM system. In this embodiment,multiple medical devices 100A, 100B, . . . , 100N transmit and receivedata from their respective host computing devices 4606A, 4606B, . . . ,4606N by means of wireless low energy radios 4700A, 4700B, . . . , 4700N(examples of which include, but are not limited to, BLE, ANT, Zigbee,etc.). The host computing devices 4606A, 4606B, . . . , 4606N transmitand receive data from MDM computing device 4600 via network 4608. Inthis embodiment, the MDM computing device 4600 manages the App 4602software distribution, configuration, settings, and data flow in acentralized fashion, for each system comprised of a medical device(i.e., 100A, 100B, . . . , 100N) and a host computing device (i.e.,4606A, 4606B, . . . , 4606N). An example of such a system can be aclinical-grade pulse oximetry system, with associated methods andapparatuses disclosed herein. An example of software distribution can bethe deployment of the Application software 4602 on the host computingdevices 4606A, 4606B, . . . , 4606N via network 4608. The host computingdevices in turn can also deploy firmware images (stored as datastructure(s) and/or file(s) in the Application software 4602) on themedical devices (i.e., 100A, 100B, . . . , 100N) via wireless connection(i.e., 4700A, 4700B, . . . , 4700N), so as to ensure all medical devicesrun the same firmware version. A data flow example can be for alarmsystems, where alarm events (e.g., SpO2 and PR upper and lower limits,off patient, device out of range, low battery, etc. event alarms) fromeach pulse oximetry system are relayed to the appropriate hospital areasand/or caregivers via the MDM computing device 4600. A configurationexample can be for configuring an Application software 4602 (that runson host computing devices 4606A, 4606B, . . . , 4606N) to have the sameconfiguration throughout the whole organization (e.g., hospitals,clinics, etc.), or to have a specific configuration that is function ofthe unit (e.g., pediatrics unit, intensive care unit, surgicalobservation unit, etc.) where the pulse oximetry system is located. Thenetwork 4604 can be used to relay/receive information to/fromthird-party computing systems and devices not connected to the network4608, or when networks 4604 and 4608 cannot be connected together (orcannot be the same) because of technical/security reasons. The networks4604 and 4608 represent one or more intranet networks and/or internetnetworks (wireless and/or wired).

FIG. 48 is a flowchart illustrating a method of providing SpO2 valuesthat exceed one hundred percent. Initially, a determination is made atblock 4800 as to whether the “SpO2 Out-of-Range Suppression” is disabled(see 4502 in FIG. 45). If suppression is enabled, the process passes toblock 4802 where the SpO2 value(s) is determined using a calcurve orplot that has a maximum SpO2 value of 100%. Any SpO2 values that exceed100% may be rounded down to 100%. The SpO2 value or values are providedto an output device (e.g., a display) as an integer number that is equalto or less than 100% (block 4804).

When a determination is made at block 4800 that suppression is disabled,the method continues at block 4806 where the SpO2 value(s) is determinedusing a calcurve or plot that has a maximum value greater than 100%. Forexample, as described earlier, the maximum value can be 107%. Thecalcurve includes or represents optical ratios (red over infrared) over100%. In some instances, a curve can be fit to the values and then theresulting curve's expression can be used to extrapolate SpO2 valuesabove 100%. At block 4808, the SpO2 value(s) is provided to an outputdevice (e.g., a display) and represented by a whole number and one ormore decimal place values (e.g., tenths place value, hundredths placevalue, etc.). Optionally, the upper limit of the SpO2 value for an alarmcan be automatically adjusted to a value over 100% (e.g., the maximumvalue over 100%). For example, as shown in FIG. 18, the upper limit inthe SpO2 Alarm Limits setting 1812 can be automatically adjusted to avalue higher than 100%.

As used herein, the terms “component”, “operation”, and “functionality”(and derivatives thereof) each refer to an aspect of the invention thatcan be implemented as hardware (e.g., circuitry), software, orcombinations of hardware and software.

As should be appreciated, the components and operations depicted inFIGS. 1-48, and the corresponding descriptions of FIGS. 1-48, are forpurposes of illustration only and are not intended to limit embodimentsto a particular sequence of steps, or a particular combination ofhardware or software components.

Aspects of the present disclosure, for example, are described above withreference to block diagrams and/or operational illustrations of methods,systems, and computer program products according to aspects of thedisclosure. The functions/acts noted in the blocks may occur out of theorder, as shown in any flowchart. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently or theblocks may sometimes be executed in the reverse order, depending uponthe functionality/acts involved. Additionally, one or more blocks can beomitted or added to the operations shown in the flowcharts.

The description and illustration of one or more aspects provided in thisapplication are not intended to limit or restrict the scope of thedisclosure as claimed in any way. The aspects, examples, and detailsprovided in this application are considered sufficient to conveypossession and enable others to make and use the best mode of claimeddisclosure. The claimed disclosure should not be construed as beinglimited to any aspect, example, or detail provided in this application.Regardless of whether shown and described in combination or separately,the various features (both structural and methodological) are intendedto be selectively included or omitted to produce an embodiment with aparticular set of features. Having been provided with the descriptionand illustration of the present application, one skilled in the art mayenvision variations, modifications, and alternate aspects falling withinthe spirit of the broader aspects of the general inventive conceptembodied in this application that do not depart from the broader scopeof the claimed disclosure.

What is claimed is:
 1. A system, comprising: a medical device,comprising: a printed circuit board-battery assembly, comprising: aprinted circuit board comprising at least one contact pad comprising anON switch of the medical device and an optical sensor, the opticalsensor comprising: at least one light source to emit light towards ameasurement site of a user; and at least one photodetector to receivelight returned from the measurement site; and a battery electricallyattached to the printed circuit board; a tape encapsulation assemblywrapped around the printed circuit board-battery assembly, the tapeencapsulation assembly comprising: a sensor window positioned over theoptical sensor; and a contact opening extending through a tapeencapsulation component for receiving a first removable tab, the firstremovable tab including a liner layer portion disposed on a firstsurface of the tape encapsulation component covering the at least onecontact pad on the printed circuit board and a tab portion disposed onan opposite second surface of the tape encapsulation component; and asecond removable tab positioned on a surface of the tape encapsulationassembly, the second removable tab including a two-sided adhesive layerthat provides an adhesive layer on a surface of the medical device whenthe second removable tab is removed from the medical device.
 2. Thesystem of claim 1, wherein the measurement site comprises one of: afinger of the user; an ear lobe of the user; a forehead of the user; anose of the user; an arm of the user; a neck of the user; or a posteriorauricle of an ear of the user.
 3. The system of claim 1, wherein theprinted circuit board further comprises: a first processing deviceoperably connected to the optical sensor; a first wireless communicationdevice operably connected to the first processing device; and a firststorage device operably connected to the first processing device, thefirst storage device storing instructions, that when executed by thefirst processing device, configure the medical device to: receivemeasurement data from the optical sensor; process the measurement datausing only a part of a biosensing algorithm to produce partiallyprocessed measurement data; and transmit, using the first wirelesscommunication device, the partially processed measurement data to a hostcomputing device.
 4. The system of claim 3, wherein the first storagedevice stores instructions, that when executed by the first processingdevice, further configure the medical device to store a serial numberassociated with the medical device in the first storage device.
 5. Thesystem of claim 3, further comprising a host computing device, the hostcomputing device comprising: a second processing device; a displaydevice operably connected to the second processing device; a secondwireless communication device operably connected to the secondprocessing device; and a second storage device operably connected to thesecond processing device, the second storage device storinginstructions, that when executed by the second processing device,configure the host computing device to: receive, using the secondwireless communication device, the partially processed measurement data;process the partially processed measurement data using a second part ofthe biosensing algorithm to produce one or more measurement values; andcause the one or more measurement values to be displayed on the displaydevice.
 6. The system of claim 3, wherein the second storage devicestores instructions, that when executed by the second processing device,further configure the host computing device to: receive an image of alabel that includes an identifier, the identifier including an originalcredential and data associated with the medical device; compute anauthentication credential using the original credential in theidentifier; compare the computed authentication credential with theoriginal authentication credential; when the authentication credentialmatches the original credential, computing a first paring credentialusing data included in the identifier that is also stored in the medicaldevice; and transmit, using the second wireless communication device,the first pairing credential to the medical device.
 7. The system ofclaim 6, wherein the first storage device stores instructions, that whenexecuted by the first processing device, further configure the medicaldevice to compute a second pairing credential, wherein the medicaldevice is paired with the host computing device when the first and thesecond pairing credentials match.